The Mechanism of Thought, Imagery, and Hallucination 9780231895460

Table of contents :
CONTENTS
LIST OF ILLUSTRATIONS
INTRODUCTION
PART ONE. FUNDAMENTALS
CHAPTER ONE. THE LAW OF EVOLUTION AND DISSOLUTION OF THE NERVOUS SYSTEM
CHAPTER TWO. THE EMOTIONAL STATE
CHAPTER THREE. THE RELATION OF THE EMOTIONS TO THE CONSCIOUS, SENSORY, OR INFORMATIVE STATE
CHAPTER FOUR. THE EXPRESSION AND THE SUBJECTIVE EXPERIENCE OF THE EMOTIONS
CHAPTER FIVE. THE WILL
CHAPTER SIX. NERVE SIGNALING
CHAPTER SEVEN. THE EFFECT OF INJURIES OF THE ASSOCIATION SYSTEMS
CHAPTER EIGHT. REPRESENTATION AND SYMBOLISM
PART TWO. THE MECHANISM
CHAPTER NINE. A DEFINITION OF THOUGHT , IMAGERY, AND HALLUCINATION
CHAPTER TEN. HALLUCINATIONS IN CERTAIN INJURIES AND DISEASES OF THE NERVOUS SYSTEM
CHAPTER ELEVEN. THE EPILEPTIC SEIZURE
CHAPTER TWELVE. THE STATE OF ATTENTION
CHAPTER THIRTEEN. SLEEP
CONCLUDING REMARKS
INDEX

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THE MECHANISM OF THOUGHT, IMAGERY, AND HALLUCINATION

T H E M E C H A N I S M OF THOUGHT, IMAGERY, AND HALLUCINATION BY

JOSHUA ROSETT P R O F E S S O R o r N E U R O L O G Y IN COLUMBIA U N I V E R S I T Y SCIENTIFIC DIRECTOR, BRAIN RESEARCH FOUNDATION, INC. NEW YORK

NEW YORK: MORNINGSIDE HEIGHTS

COLUMBIA UNIVERSITY 1939

PRESS

COPYRIGHT COLUMBIA

UNIVERSITY

1939

BY

PRESS, N E W

YORK

FOREIGN A C E N T S : OXFORD U N I V E R S I T Y P R E S S , H u m p h r e y M i l f o r d ,

Amen

House, London, E.C. 4, England, AND B. I. Building, Nicol

Road,

B o m b a y , I n d i a ; KWANC HSUEH PUBLISHING HOUSE, 1 4 0 P e k i n g R o a d ,

Shanghai, China; MARUZEN COMPANY, LTD., 6 Nihonbashi, Tori-Nichome, Tokyo, Japan M A N U F A C T U R E D IN T H E U N I T E D STATES OF A M E R I C A

Acknowledgments The author wishes to exfress his gratitude to Nina Bull for her valuable services in connection with this work; and to Mari B oilman and Fitzhugh Boggs for their efficient technical assistance.

CONTENTS INTRODUCTION

PART ONE.

FUNDAMENTALS

I . T H E L A W OF E V O L U T I O N AND DISSOLUTION OF T H E N E R V O U S SYSTEM

The operation of the Law of Evolution and Dissolution of the Nervous System. — Summary. — References I I . T H E E M O T I O N A L STATE

The physical basis of the emotions. — The function of the emotions in the redistribution of the bodily energies. — The suspension of certain vital activities in the course of the emotions.— The arrest of digestion during a strong emotion. — Changes in the blood sugar content in emotional states. — Increased supply of oxygen during emotional stress. — Enhancement of the circulatory activity in states of emotion. — The redistribution of the quantities of blood determined to different parts of the body in the emotions. — Provisions for the dissipation of excess temperature during muscular exertion. — Increase in the number of red blood cells during muscular activity. — The reduction of the coagulation-time of the blood in the strong emotions. — Diminished fatigability of the muscles in the strong emotions. — The greater vividness and permanence of the memory of experiences associated with emotional states. — Summary. — References I I I . T H E R E L A T I O N OF T H E E M O T I O N S TO T H E CONSCIOUS, SENSORY, OR I N F O R M A T I V E STATE

Anatomic and physiologic considerations. — The biological significance of the sensory state. — The nerve impulse. — The course of the cerebral nerve pathway. — The thalamus. — The cerebrospinal and the autonomic nerve systems. — The three divisions of the autonomic nerve system. — The cooperative reciprocal action of the antagonistic divisions of the autonomic system. — The same action of the autonomic system in different bodily states. — The local activities of the autonomic system. — The oscillating balance of the body. — The permanence and specificity of the bodily changes resulting from temporary emotional disturbances. — Summary. — References

VUl

CONTENTS

I V . T H E EXPRESSION AND THE SUBJECTIVE EXPERIENCE OF THE E M O -

67

TIONS

The cerebrum from the point of view of an integral part of the body. — The functions of the thalamic plexus. — The effect of nerve impulses arriving from the cerebral cortex at the thalamus. — A general formula for the kind of modification undergone by nerve impulses in their passage through the cerebral cortex. — An example of the different effects of nerve impulses traveling by the short and the long route respectively. — Cognition and recognition. — A definition of sensation and feeling. — Knowing and feeling. — The relation of feeling and sensation to the sensory receptor organs. — A partial reconciliation of the modern point of view of the emotions with the James-Lange theory. — Summary. — References

103

V. THE WILL

Non-volitional and volitional acts. — The motive of a volitional act. — Its genesis. — Definition of a volitional act. — The pyramidal tract as the nerve pathway for the conduction of the will. — The relation of the will to the cerebral cortex. — Summary.— References VI.

NERVE SIGNALING

109

Summary. — References V I I . T H E E F F E C T OF INJURIES OF THE ASSOCIATION SYSTEMS .

.

.

.113

The elements of the memory of a situation. — The repository of memory. — The inferences drawn from the aphasias. — Anatomical facts. — The ultimate seat of memory. — Disintegration of complex memories. — Summary. — References VIII.

REPRESENTATION AND SYMBOLISM

The biological causes of representation and symbolism. — Direct representation. — Indirect representation. — The part of representation in education. — Representation in government.— Representation in art. — Permanency of effects. — Symbolism.— Symbolism a means for responding to a complex situation as a whole. — The symbol a means of conserving energy and. time. — The evolution of representation into symbolism. — Symbolism in writing. — Symbolism in gesture-language. — Symbolism in government.— The confusion of likeness with identity by means of comparisons and other figures of speech. — Conditioned reflexes. — The main conditions for the effectiveness of symbols. — Responses to certain "neutral" stimuli inherited. — The relation

124

CONTENTS

ix

of the conditioned to the unconditioned stimulus. — An explanation of the chain reflex. — The effectiveness of the same symbol in evoking different reactions. — Illusion and delusion. — Art. — Redintegration. — Suggestion. — Summary. — References PART IX. X.

A

TWO. THE

MECHANISM

D E F I N I T I O N OF T H O U G H T , I M A G E R Y , AND H A L L U C I N A T I O N

HALLUCINATIONS

IN

CERTAIN

INJURIES

AND

DISEASES

OF

.

.155

THE

NERVOUS SYSTEM

157

Summary. — References XI.

T H E E P I L E P T I C SEIZURE

171

The minor seizure. — Jacksonian epilepsy. — The normal epileptoid or startling reaction. — Summary. — References XII.

THE

STATE

OF A T T E N T I O N

182

Definition of attention. — The reason for the dominance of certain sensations and feelings at any one time. — The wavelike procession of the bodily needs. — The breach in attention made by strong stimuli. — The substitution of the cerebral for the vegetative functions. — The fluctuation of attention. — Mimesis.— Learning by imitation. — The attainment of the same end by different means. The persistence of the most appropriate reaction in the course of learning. — Auditory and other intermediary stimuli in acts of imitation. — The bearing of experience of a general kind on concrete tasks. — Mental attitude. — The effect of indirect intermediary mimetic stimuli. — The factors of clarity and intensity in states of attention. — Further proof that a given bodily need determines a corresponding state of attention. — Sensation a guide to memories of past experience. — The induction of sleep by narrowing the scope of attention. — Suggestion. — Concentration of attention. — The part of training and heredity in determining the quality of attention. — The muscular manifestations of the state of attention. — The relation of the stages of attention to the nerve pathway. — Summary.— References XIII.

SLEEP

The condition of the body in sleep. — The rhythm of sleep.— The nerve apparatus for the regulation of sleep. — The causes of sleep. — The stages of sleep. — First stage, the activity of thought. — Second stage, the activity of imagery. — Transition between the first and the second stages of sleep. — Third stage,

224

X

CONTENTS

hallucination. — T h e reason for the recurrence of certain thoughts at certain times. — Recurring dreams. — The conception of relations in most instances faulty. — Dreams of falling from a height. T h e startle which wakens the sleeper. — T h e disintegration of memories in the onset of sleep. — The duration of a dream. — T h e effect of dreams on future behavior. — The muscular manifestations of sleep. — Awakening. — Hallucinations. — Sleep induced by the action of drugs. — Summary of the factors involved in sleep. — References CONCLUDING REMARKS

270

INDEX

273

LIST OF ILLUSTRATIONS I. A Schema of the Lateral View of the Cerebrospinal and Autonomic Nerve Systems

41

2. A Combustible String and a Parallel Schema of the Arrangement of Nerves

46

3. A Schema from A. Meyerson's Human Autonomic Pharmacology, X I I

55

4. Diagram of Cat's Brain (After Bard)

98

5. A Diagram of the Arrangement of the "Long" Association Systems and of the Receptive Areas of the Human Cerebrum 119 6. The Representation of Conditions or of Abstract Entities by Concrete Objects 133 7. The Evolution of Representation into Symbolism in Written Language (from Ilin's Black on White) 134 8. "Paternoster"

135

9. Outline Drawings of a Motion Picture of an Epileptic in Convulsion . 176 10. A Diagram of the Manner in Which a Point in Space Can Be Reached by Any One of a Number of Movements and Postures

197

1 1 . Economo's Schema of the Center for the Regulation of Sleep . . . .

228

12. Fulton and Bailey's Localization of the Center of Sleep

229

INTRODUCTION

INTRODUCTION Ever since man became man there has hardly ever existed a race of savages who did not postulate causes for the differences which take place in man's consciousness from time to time. During the waking state man is adjusted to more or less predictable changes in his surroundings—predictable, because experience has shown nature at large to be subject to fixed physical laws and rigidly confined within boundaries of space and time. In the waking state, man's activity, which he can exert at will, is plainly the result of certain internal and external movements of the body and the limbs, and all activity is observed to cease after death. Such is not the case in sleep. In that state of being the surroundings appear to be divested of all physical laws, and changes are not, therefore, calculable in advance. Neither space nor time exist, so that the same thing can be in more than one place at the same time, and more than one thing can be in the same place at the same time. The difference between the living and the non-living world has disappeared; inanimate objects can speak and move by the power of their volition and persons long since dead and decomposed live and act again. The sleeper feels himself executing a number of acts, yet learns upon awakening that such activity was not the result of any physical movement of his body or his limbs. By witnessing the behaviors of the epileptic and the insane, the foregoing subjective experiences are corroborated by experiences which are to a certain extent objective. The result of such subjective and objective experience is a universal belief in two different kinds of existences. One, a physical existence, which manifests itself to man in his wide-awake conscious state; the other, a metaphysical or supernatural existence, which is manifested to man in the states of sleep, of epilepsy, and of insanity. It is therefore no wonder that the ancient and mediaeval thinkers were as much concerned with the solution of the problem of consciousness as we are. Their premises, however, were deeply rooted in fable and tradition, and the procedure they employed contained a singular inconsistency. Unlike the modern mystics, they were aware that the world of facts manifests itself

4

INTRODUCTION

to us through our sensory receptors, and that the mind contains nothing but what is furnished it by these organs. It might have been expected, therefore, that in the effort to solve the problem of the mind, they would exercise their receptor organs—the eyes, the ears, the touch corpuscles, and the others—for the acquisition of the necessary facts. T h i s they failed to do. Instead, they exerted the powers of the mind in the vain hope that the factors requisite for the solution of the problem of the mind might thereby be obtained. T h e facts at their disposal thus remaining scanty, their arguments contained wide gaps, which they filled in by arbitrary assumptions of colossal magnitude and with the unbounded license of the poet and the dreamer. Most of them were indeed as much poets as they were logicians and they hardly ever hesitated to mix facts with fancy. T h e earliest speculations that we know of regarding the relation of the mind to the body may be gleaned in the traditions of the Babylonians, who apparently located the mental functions in the liver. T h e inspection of the internal organs of the sacrificial animals by the Romans is significant of a belief that those organs are the seat of supernatural influence. T h e ancient Hebrews did not believe in the existence of an immortal soul, that belief having insinuated itself among them during their Babylonian exile. A number of expressions in the O l d Testament are indicative of vague beliefs that the blood is the essence of life, that the bowels are the seat of the emotions, and that the seat of the will is in the heart. Alcmaeon of Crotona ( i ) , who lived in the sixth century B. C., ascribed the functions of mentality to the heart. Hippocrates, about 500 B. C. ( 2 ) , the Greek father of medicine, maintained emphatically that the brain was the seat of thought, imagery, hallucination, and of all the emotions, and that epilepsy and insanity resulted from its disease or injury. Such rational opinion, based on clinical and anatomical facts, soon gave way to an unbridled idealism. Plato ( 3 ) was much concerned with the soul. H e held that the brain was a lump of marrow, the same as that contained in the bones, and that its rotund shape, the symbol of perfection, was intended by the Creator for the seat of the soul. Aristotle ( 4 ) recognized the fact that the experience of the elementary sensations could not of itself account for our awareness of concrete situations and that such an awareness was brought about by a correlation of the elementary sensations with thought, which was a function of the soul. H e was of the opinion that the brain, far from being the seat of the soul, was merely an apparatus for cooling the blood before it passed to the heart. Theophrastus, born 372 B. C. ( 5 ) , the successor of

INTRODUCTION

5

Aristotle, scouted the Platonian hypothesis of the unreality of the world outside of our ideas, and maintained that we must accept the evidence of our senses. Most of what is left of his writings consists of a detailed critical review of the opinions of his predecessors and contemporaries regarding the nature of the elementary sensations. H e disposes unceremoniously of the fallacious assumptions of Empedocles, Anaxagoras, Diogenes, and Democritus, and does not hesitate to brand their statements as fanciful and childish. H e gives little hint of his own opinions regarding the operation of the sensory state, but we obtain a glimpse of them from a passage in which he approves of Clidemus: Clidemus alone spoke with originality in regard to vision; for the perceptive power of the eyes, he says, is due solely to their being transparent. W e perceive with our ears because the air bursts in upon them and causes there a motion. With our nostrils we perceive in the act of inhaling the air, for there the air enters into some kind of combination. Savours and heat and cold are perceived by means of the tongue because it is spongy. With the rest of the body we perceive other than the qualities named. T h e ancients were ignorant of the function of the nerves, which they confused with the tendons. It was not until the second century of the Christian Era that Galen ( 6 ) , who is said to have discovered the circulation of the blood long before H a r v e y , demonstrated the difference between sensory and motor nerves. H i s discoveries were largely discarded or forgotten during the Dark Ages. Saint Thomas' ( 7 ) analysis of the sensations, amazingly clear considering the dense ignorance of the twelfth century, does not differ in principle from that of his predecessors. Like Aristotle, he is of the opinion that the separate sensations cannot of themselves afford an idea of concrete situations, and he postulates the existence of a sensory entity which correlates the different sensations and integrates them into a counterpart of real existences. T h a t entity is the soul which, according to him, is of different orders. Lowest in the sensory hierarchy is the "vegetative" soul, which appertains to the needs of the body. T h e "sensitive" soul, which feels, is next higher in rank. T h e "intellective" soul, which knows, is the highest and partakes of the "angelic" attributes. Man's place in creation is therefore between the angels and the animals. A remarkable conclusion at which he arrives is that the experience of some of the sensations is productive of a change in the organism experiencing them—a conclusion which will figure prominently in the present thesis. Francis Bacon, 1 5 6 1 - 1 6 2 6 ( 8 ) , was a strong exponent of experiment and

6

INTRODUCTION

observation as the means of acquiring knowledge. But such was the pressure of the prevailing superstition of that age that in the effort at solving the problem of the conscious state, he fell a victim to traditional beliefs. Consciousness was, accordingly, an attribute of the soul, which was the inspired essence made of God's breath at the moment of creation, and could be understood only by means of revelation. H e admitted, however, the existence of a "produced" soul, more or less susceptible of study. Descartes ( 9 ) , a contemporary of Bacon, designated the brain as the seat of the soul, where alone it understands, imagines, and perceives by means of nerves which extend from it to all parts of the body. H e divided the conscious state into the affections of the mind—the "passions"—and the natural appetites. T h e latter are regulated by means of nerves which extend to the stomach, the oesophagus, and other internal organs. T h e affections of the m i n d — j o y , grief, sadness, love, hate—are brought about by means of nerves which extend to the heart. H e r e we see the first faint adumbrations of the James-Lange theory of the emotions, promulgated late in the nineteenth century. T h u s speculated the great philosopher-poets for upwards of two thousand years, some from logic, others with the help of casual observation, still others from assumed revelation. T h e true revelation came when, the microscope having attained a certain degree of perfection, the brain and the nerves were discovered to consist of tenuous filaments, the continuations of nerve cells. These were soon interpreted to subserve the function of conducting impulses from the receptor organs to the muscles and the glands. T h e invention of the microscope coincided with the dawn of the machine age. T h e rapid evolution of the latter furnished the equipment for investigation. Philosophy and psychology began to exhibit in their argument a degree of clarity previously unknown. A good illustration is the manner in which H u m e , 1 7 1 1 - 7 7 ( 1 0 ) , outlines the relation of the complex mental functions to the functions of sensory reception. H e calls attention to the relative vagueness with which past experiences are recalled in thought, as compared to the vividness of immediate sensory reception. " E x c e p t , " says he, "the mind be disordered by disease or madness, they [the thoughts] can never arrive at such a pitch of vivacity as to render these perceptions [thought and sensory reception] altogether undistinguishable." It will appear below that the difference between thought and hallucination implied in Hume's statement, is incomplete; but whatever difference is implied is expressed with greater succinctness than the combined expositions of all

INTRODUCTION

7

the philosophers and poets of the preceding twenty centuries and more. In the same essay of seven short pages, H u m e proves with incontestable logic that the imagination never creates anything totally new, and that no matter how unbridled it may be, its product is after all but a composition of experienced objects and conditions arranged into new relations. It is worthy of note that almost a century later this concept reappeared in such widely separated domains of inquiry as John Stuart M i l l ' s ( 1 1 ) analysis of the significance of human effort in political economy and Herbert Spencer's ( 1 2 ) discussion on the standards of art. If it should be asked: W h a t are the causes which have operated for the progress of clarity and definiteness of thought, hand in hand with the progress of the machine age? the following answer may be given. T h e evolution or the decay of organs and functions is brought about by the limiting mold of environing conditions. W h e n man's environment is constituted by the machine, on which his livelihood depends, all of his functions must accommodate themselves to the machine. T h e efficiency of a machine, however, depends on the accuracy with which its several parts are fitted together to subserve a definite and concrete end. In accordance with these attributes of accuracy of construction and definiteness of purpose of the machine, man's thoughts, if he is to survive, can no longer wander in a dim atmosphere of pure idealism, but must become accurately adjusted to real existences. W i t h the full swing of the machine age in the middle of the nineteenth century, the criticism of the metaphysical method of investigating the mind became pronounced. A single passage from Buckle's History of Civilization in England ( 1 3 ) will suffice as an illustration: In Metaphysics [says Buckle], the mind is the instrument as well as the material on which the instrument is employed. T h e means by which the science must be worked out, being thus the same as the object upon which it works, there arises a difficulty of a very peculiar kind. This difficulty is the impossibility of taking a comprehensive view of the whole of the mental phenomena j because no matter how extensive such a view may be, it must exclude the state of the mind by which, or in which, the view itself is taken. T h e same period witnessed the promulgation by Charles Darwin of the laws which underlie the origin of organic species. T h e latter dealt a stupendous blow to ancient beliefs, while it gave impetus to the study of every branch of biology. B y a correlation and organization of a vast number of ascertained facts, the separate sciences assumed definite forms, which philos-

8

INTRODUCTION

ophy was not slow to synthesize into general principles. One such general principle, elucidated by Herbert Spencer ( 1 4 ) , is of especial interest in connection with the work before us. It is the principle that any organic function, being the resultant of a number of chemical, physical, and mechanical movements, is subject to the laws of motion. Under the continuous incidence of a force, the motion of a body gains in momentum with the passage of time, and the magnitude of a force that could arrest or could deviate the body from the direction of its motion must in consequence be the greater the longer the duration of the movement. John Hughlings Jackson ( 1 5 ) , who was an admirer and follower of Spencer, applied this law of motion to the behavior of nervous functions under conditions of stress. H e observed that in injuries or diseases of the brain which are productive of disorders of speech, the latest acquired and most complex phases of that function are most profoundly involved and are the last to recover} while the earlier acquired and simpler phases of that function are the least involved and are the first to emerge during recovery. H e called the principle in question The Law of Evolution and Dissolution of the Nervous System. A familiar example of the operation of this law is afforded by the behavior of the nervous functions in alcoholic intoxication. Reason and judgment are recently acquired nerve functions, in the course of an individual's lifetime. In poisoning by alcohol, these functions are the first to succumb and they are the last to appear during recovery from the action of the poison. On the other hand, respiration is phylogenetically a very old function j it is the last to be affected by the action of the poison and is the first to recover. T h e operation of the Law of Evolution and Dissolution of the Nervous System will be discerned in a number of the forthcoming discussions of the different phases of the conscious state. An apparent contradiction to that law will be pointed out in the first chapter of this book and will be explained in the succeeding chapters. REFERENCES

1. Brown, Horace. " T h e Anatomical Habitat of the Soul." The Annals of Medical History, V ( 1 9 2 3 ) , 1. 2. T h e Genuine Works of Hippocrates. Chapter on " T h e Sacred Disease." Trans, from the Greek by Francis Adams. N e w York, William W o o d and Co. 3. Plato. Dialogues. 4. Aristotle. O n the Soul. Trans, by W . S. Hett. Cambridge, Mass., Harvard University Press, 1935.

INTRODUCTION 5. Greek Physiological Psychology—Theophrastus. T h e Macmillan C o .

9 G . M . Stratton. N e w

York,

6. Oeuvres de Galien. T r a d , par D r . C h . Daremberg. Paris, J. B. Balliere, 1854. 7. Güson, Etienne. T h e Philosophy of Saint T h o m a s Aquinas. T r a n s , by E d w a r d Bullough. Cambridge, W . Heffer and Sons, 1929. 8. Bacon, Francis. T h e Advancement of Learning. London and N e w Y o r k , T h e Colonial Press, 1900. 9. T h e Method, Meditations and Philosophy of Descartes. Trans, by John Veitch. N e w Y o r k , T u d o r Publishing C o . , 1 9 0 1 . 10. 11. 12. 13. 14.

Hume, David. O n the Origin of Ideas. Mill, John Stuart. Principles of Political Economy. Spencer, Herbert. Education. Buckle, Henry T h o m a s . History of Civilization in England. Chapter I I I . Spencer, Herbert. General Principles, Principles of Biology, and Principles of Psychology.

15. Jackson, J. Hughlings. Selected W o r k s . London, Hodder & Stoughton, 1931—32.

PART

ONE

FUNDAMENTALS

CHAPTER ONE T H E L A W OF E V O L U T I O N A N D DISSOLUTION THE

NERVOUS

OF

SYSTEM

One of the basic problems underlying the mode of operation of the mental functions, which has so far defied attempts at solution, is their persistence under depressing conditions beyond the point at which the elementary sensations are extinguished. It will be readily admitted that in the history of organic evolution the elementary sensations of contact, pain, sound, and the others are of much older standing than are the functions of thought, imagery, and hallucination. That such is the case might be easily inferred from the fact that the mental functions are gradually built up in the individual in the course of years by a process of integration of sensory impressions. And what is true of the difference in the ages of these two classes of sensory functions must be likewise true of the structures which give rise to those functions. It is a fact well known to biologists that the immense association apparatus of the human cerebrum is a relatively recent evolution of nervous structures. Anatomic and psychologic studies corroborate the truth of this proposition. T h e child's brain is small, as compared with that of the adult, and the association apparatus of its cerebrum is plainly seen to be undeveloped ( i ) . As soon as a child is able to give an account of his subjective experiences, it may be readily ascertained that his elementary sensations are already far advanced, while his powers of reasoning and judgment, his imagery, and the content of his dreams are still crude as compared with those of the older person, whose impressions, in a varied environment, have been integrated into a complex mental structure. It would therefore seem that, tested by Jackson's (2) Law of Evolution and Dissolution of the Nervous System, 1 the highly complex functions of thought, imagery, and hallucination should succumb before the elementary sensations to the action of a general nerve depressant, and that they should be the last to recover. That exactly the reverse is the case may be observed 1

See Introduction above.

14

LAW

OF

EVOLUTION

AND

DISSOLUTION

in every depressing condition of the nervous system whose onset or whose termination is gradual. T w o examples from my own records, given below, are sufficiently familiar to physicians and laymen to be recognized by them as pertinent and true in every part. The first is illustrative of the fact that under the action of a drug whose effect on the nervous system is representative of a large class of depressing agencies, the functions of thought, imagery, and hallucination endure beyond those of sensory reception. T h e second illustrates the fact that during the process of recovery from the action of a depressing drug, which is likewise representative of a large class of depressing conditions, the functions of thought, imagery, and hallucination become subjectively manifest before those of the elementary sensations. 1. Ethylene anesthesia.—"I admired the large, bright, clean hall of the hospital along which I was wheeled on the way to the operating room. In a few minutes I was on the operating table, intent on watching the action of the anesthetic. After the mask was applied, I was requested by the anesthetist to inhale deeply, which 1 did. H e talked to me jokingly, asking me, during the first inhalation, whether my trouble was in my brain. I shook my head in reply and heard him laugh and say: 'Very well then we won't cut into t h a t — H e continued talking, but his voice sounded increasingly small and distant until I could not hear it at all. It seemed as if everything about me disappeared and I was utterly alone in a dark void. Quite suddenly, in the midst of that void, I found myself in a large, bright and clean marble hall of so great a length that I could not see its end. I recognized it. It was the hall which led to the operating room, yet at the same time, it was the deep, subterranean vault painted by Usher, the hero of Poe's story 'The Fall of the House of Usher.' It must be that vault, I said to myself. And indeed, amidst the profound stillness there suddenly came clashing, clanging sounds of a gong which I recognized to be the sounds made by the magic silver shield which dropped from the wall to the marble floor at the feet of the brave knight who entered the enchanted palace to kill the wicked dragon, in another part of the same story. ' H o w glorious,' I said to myself, and lapsed into unconsciousness." 2. Nitrous oxide anesthesia.—"A second or two after the feeling of asphyxiation, consciousness—thought as well as sensation—was completely and, as far as I could remember, suddenly extinguished. How long complete unconsciousness lasted, I had of course no way of knowing, except from the subsequent account of the dentist who told me that the entire process lasted hardly more than two minutes. The first sign of returning

LAW

OF

EVOLUTION

AND

DISSOLUTION

15

consciousness was subjectively manifested by a feeling of movement. I was somewhat chagrined by the fact that I could not readily ascertain whether I was moving with relation to the surroundings or whether they were moving with relation to me. I then made an effort to discover whether the movement was in a straight or in a curved line. My mind next began to dwell pleasurably on the prevailing profound stillness. I reasoned that my supremely placid and passive sense of pleasure was due to the perfect restfulness of body and mind in the absence of the great number and variety of sounds and sights and contacts which assail the body under ordinary conditions. But immediately the idea of sound came to my mind, I heard a single clicking, cracking sound repeated five or six times at short, regular intervals. I tried to discover what had caused them, and said to myself, 'I suppose they are the natural accompaniments of the movement.' Immediately I said this, I was dissatisfied with having offered so meaningless an explanation. It then occurred to me that the sound might be due to a little hammer striking against a slowly revolving, large iron wheel, but I soon abandoned this idea and decided that some projection on the wheel struck against a neighboring object once at every revolution. At the same time it occurred to me that my tooth must have already been extracted and that I ought to wake up. In order to expedite the waking up, I took deep breaths and said to myself, 'This is my opportunity to watch the order in which sensations return.' The prevailing quiet was still very profound. I wondered whether I ought to open my eyes, but so pleasurable was the sense of restfulness that I was very reluctant to do so. I reasoned, however, that I was doing an injustice to the dentist by keeping him in suspense, and opened my eyes slightly. As in a deep mist I saw through the window in front of me the dim outlines of the towers in the center of New York. As I gazed at them intently, they were rapidly assuming increasingly distinct outlines, while the mist which enveloped them was rapidly disappearing. It disappeared completely in another few seconds and the towers stood out in clear, hard lines. I became aware of the presence of the dentist and nurse beside me, the former holding out a bottle of whiskey and saying, 'Will you have a little of this?' I was indisposed to speak and replied by shaking my head in the negative. I was then amazed at the complete absence of pain at the site of the extraction and still more so by the complete numbness of my entire body. Even as I thought of it, the numbness began to disappear from above downwards, the feet being the last to recover." The foregoing are by no means outstanding instances of the extent to

16

L A W

OF

E V O L U T I O N

AND

D I S S O L U T I O N

which the composite mental functions outlast those of sensory reception in generally depressing conditions. T h e y are average examples, such as almost anybody could supply from his own experience. An analysis of such a subjective experience brings out the remarkable fact that although in its details it is plainly subject to the L a w of Evolution and Dissolution of the Nervous System, it is in opposition to that law as a whole. THE

O P E R A T I O N OF T H E L A W OF E V O L U T I O N AND DISSOLUTION OF T H E NERVOUS

SYSTEM

Our conception of the significance of any situation is based on its relation to us and to other objects and conditions. W h e n a child learns that a certain person is his D a d d y , that a thing named "chair" is a thing to sit on, he has learned the relation of " D a d d y " and "chair" to himself and to certain other objects and conditions. From babyhood to old age we acquire an increasing number of significances of any entity. T o the baby the significance of a lead pencil is the fact that it can be readily grasped and put into the mouth; to the young child, it is the capacity of the object for leaving a mark on paper; to the older child, it is that of a writing instrument; to the adult, according to his particular experiences, it has a number of other significances, such as the easiest way of manufacturing it, or the price it will fetch in the market. These mental acquisitions are manifested in the function of expression. T h e young child can name a certain number of objects and conditions; the older child, having experienced the relations in which they stand to one another, can combine the names of those objects and conditions into corresponding relations—can form sentences. T h e still older child, with a greater amount of experience with such relations, can combine sentences into corresponding propositions. It will therefore be seen that in the course of the development of the mental functions, memories of relations in which objects and conditions stand to one another are acquired after the memories of the objects and conditions themselves. A n d the operation of the L a w of Evolution and Dissolution in the two examples given will be discovered from the fact that, under the action of the depressants, the memories of relations are faulty while those of the objects and conditions related are sound. T h u s , in Poe's story, the sounds made by the falling of the magic shield to the marble floor have no relation, or only a very distant and indirect relation, to the

LAW

OF

EVOLUTION

AND

DISSOLUTION

17

vault painted by the hero of the story; while in the subjective re-experience of the contents of that story under the action of a depressant, that relation is proximate and direct. Again, in the course of recovery from the anesthesia of nitrous oxide, the subjective experience of the sense of movement may have been due to the unequal depression of the different parts of the vestibular nerve apparatus of balance. But the relationing of the sense of movement of one's body to the vivid image of a slowly revolving large iron wheel is a faulty relationing. Note further the manner in which such faulty relationing improves, step by step, with the progress of recovery. First the very faulty relationing of the clicking sounds to the revolution of the wheel expressed in the proposition, " I suppose they are the natural accompaniments of the movement"; next, the sense of dissatisfaction with such an explanation; after that, the more concrete yet rather faulty relation of a little hammer to the wheel; and finally, on the very verge of awakening, the more natural relation of the particular sounds to a revolving wheel—an unevenness of its circumference striking at a neighboring object once at every revolution. Although in the details of the enduring complex mental functions we can discern the operation of the Law of Evolution and Dissolution, yet the fact that they have endured beyond the relatively simpler functions of pain, hearing, contact, and in fact of all sensory reception, makes the phenomenon as a whole in obvious opposition to that law. The importance of discovering the factors which make for such opposition becomes all the greater from a consideration of the following facts: Not only are the composite mental functions more enduring than those of simple sensory reception but, as might be seen from the examples given, and as will be more fully shown in those below, the depression of sensory reception initiates the activity of the complex mental functions; and the degree of vividness with which past experiences are subjectively re-experienced in the process of mental activity is in a certain proportion to the degree to which the function of sensory reception is suppressed. SUMMARY

1. Under conditions which are generally depressing to nervous function, as exemplified by general anesthesia, the mental functions, although disorganized, persist beyond the point at which sensory reception is extinguished.

L8

LAW

OF

EVOLUTION

AND

DISSOLUTION

1. Therefore, although in their detail the mental functions are subject to Jackson's Law of Evolution and Dissolution of the Nervous System, they are independent of that law as a whole. 3. A diminution of sensory reception is a condition for the initiation of mental activity. REFERENCES

1. Flechsig, Paul. Anatomie des menschlichen Gehirns und Rückenmarks auf myelogenetischer Grundlage. Leipsig, Georg Thieme, 1920. 2. Jackson, J. Hughlings. " T h e Croonian Lectures on the Evolution and Dissolution of the Nervous System." Brit. Med. Joum.y I ( 1 8 8 4 ) , 591, 660, 703 (Lectures I, II, I I I ) .

CHAPTER TWO THE

EMOTIONAL

STATE

T h e experience of sensation on the one hand and the mental activities of thought, imagery, and hallucination on the other, constitute jointly or separately the conscious or sensory state. T h i s state cannot be understood without at least a general comprehension of the mechanism and significance of the emotions. A brief sketch of the latter is therefore an indispensable, though it must be confessed a rather difficult, preliminary to an exposition of the mechanism and of the significance of the several factors which constitute the conscious state. THE

PHYSICAL

BASIS

OF

THE

EMOTIONS

I t will perhaps be conducive to a clearer conception of the physical basis of the emotions if we are permitted to indulge for a moment in the absurd speculation that there may exist a body so utterly inert that it is not in the least affected by the impacts of the surrounding forces. T h e proposition is absurd because there could be no manifestations of any kind of impacts against such a body. Any manifestation of the impact of a force against a body is due to the resistance offered to the progress of the force, whereby the magnitude of the latter or its direction, or both, are changed. If we carry the abstraction further by assuming the existence of a body of absolute tenuity, such a body, it is true, would offer no resistance to the progress of a force, but then there would be no impact. A body of absolute tenuity is, however, no body at all. T h e living organism, far from being an inert body, is, in the totality of its properties, comparable to a kind of rubbery substance which, yielding rather easily to the impacts of the surrounding forces, springs back toward its original form after the pressure of the outside force is released, so that it maintains throughout life a certain degree of chemical, mechanical, and physical constancy, that is, it retains its individuality ( i ) . A more accurate statement of the fact involved is the following: As long as the organism yields to a certain extent to the pressure of the surrounding forces and springs back to nearly its original state upon release of that pressure, so

20

THE

EMOTIONAL

STATE

that, while becoming slightly changed by the repeated impacts of the surrounding forces, it still retains in large part its individuality, it lives; when it loses to any considerable extent the property of yielding largely and of largely reassuming its original state, it dies. Unless it yields readily and springs back readily, it is, like a piece of brittle marble, shattered to fragments by the hammering of the external forces. T h e changes which take place in a piece of soft rubber or hard steel, as a result of the blows of a hammer, are of many kinds—mechanical, thermal, electrical, and so on. T h e force which sends the hammer flying in the opposite direction is the return of the temporarily changed piece of rubber to its nearly original state. T h e changes which take place in the living body as a result of its collision with the surrounding forces constitute the physical basis of the emotions; the external manifestations of those changes constitute the expression of the emotions; and these are indexed by certain changes in the nervous system known as the feelings of an emotion. It will therefore be seen that the impressions received by the living organism as a result of the impacts of the surrounding forces could not possibly be sensory impressions—could not possibly be informative to the organism of the conditions of its environment—without a concomitant bodily change. M o r e exactly stated, it is this change which informs the organism of its environing conditions. And it is this change in the living body which constitutes an emotion. T h e sensory or the conscious state—the state of being informed—therefore owes its existence to the bodily emotions and it could not possibly manifest itself otherwise. T h e return of the elastic living body to its nearly original state after a collision with an outside force is known as its "response." With respect to the time which elapses between the impact of a force against a body and its response, it must be borne in mind that the latter may take place immediately, as when the hammer rebounds when struck against an anvil; or it may be postponed, as when a spring, which is wound up and latched, remains in a state of tension for a variable length of time, until released. In the case of the living body a somewhat closer analogy of the duration between the impact of a force against it and its "response" is the time which elapses between the compounding of chemicals into an explosive substance and its explosion upon the application of a spark. Once the compounding of the chemicals has been effected, it is ready to explode the moment a spark is applied, though the latter may be delayed.

THE

EMOTIONAL

STATE

21

If it is by means of the changes—the emotions—which take place in the body that it is "informed" regarding the conditions prevailing in its surroundings, a provisional assumption is that, as the "information" refers to specific conditions outside the organism, the bodily emotions must also be of a correspondingly specific nature. T H E F U N C T I O N OF T H E EMOTIONS IN T H E REDISTRIBUTION OF T H E BODILY

ENERGIES

In time of peace the energies of a well-organized community flow along many different channels for the common good. In rude societies, by far the largest amount of energy is spent in the activities which subserve the basic necessities of life: in obtaining food and shelter, in providing a certain amount of protection against possible enemies, in mating, and in other indispensable activities. In proportion as the labor which subserves the immediate support of life becomes more effective, the surplus energy is devoted to tasks tending to increased future security, to the facilitation of the basic activities and to more amusement and recreation. Metals are worked, cattle are domesticated, forts are built for protection against possible attacks, and the young are systematically taught the trades and arts which they are to pursue in years to come. In highly civilized communities, where the labor for the satisfaction of immediate needs is very efficient, a large part of the surplus energy is devoted to making life enjoyable in the present by multiplying comforts, luxuries, and amusements, and to increasing its security for a relatively long time to come. So much of the energy of a civilized society is spent in providing for future probable or possible needs that it supports and trains its young for nearly one-third of a lifetime on account of what they may contribute later j and large numbers of persons of both sexes devote the labor of their entire life to occupations which may bear fruit only in the next generation, and frequently indeed not for many generations to come. But let the peaceful activities of such a highly civilized community be interrupted by some catastrophe—the invasion of a foreign enemy, an inundation, or a conflagration—and the manner in which the energies are distributed is immediately changed. All labor intended to bear fruit in the more or less distant future is largely reduced or entirely discontinued. The pleasures and luxuries of life are eliminated. New canals, bridges, and roads are not built, new mines are not sunk, experimental laboratories are closed.

22

THE

EMOTIONAL

STATE

The education of the young is suspended. All energies now flow along a few narrow channels. The life of the community is immediately endangered, and the problem before it is not security in years to come, but to tide over the present emergency. The population becomes sharply divided into two parts. One is immediately engaged in fighting the calamity; the other labors to support the life of the fighters and to furnish them with tools or weapons. An outsider who might witness such a change in the life of a community would first of all be impressed by the sudden general commotion. Upon closer study he would perceive a certain order and design. There has taken place a general redistribution of the community's energy, with the result that it is concentrated into few channels. H e would perceive that the warehouses, instead of being stored periodically with provisions for future use, are now being rapidly emptied; and, strangely enough, although the circulation of energy-containing substances among the members of the community is proceeding at a livelier rate than before, the population is deprived of luxuries, comforts, and to a large extent of necessities. Upon looking for the cause, he would find a vastly increased consumption of these energy-containing substances by the contingent of the population immediately engaged in overcoming the emergency. Upon still closer study, the curious observer would gain an insight into the mental state of this community. H e would find it to have reverted to a rather primitive type. H e would have little difficulty in discovering that feelings of fear, anger, exultation, rage, joy, sorrow, indignation, run high; but that there is little of that deliberation, of that detached, cool judgment which, on the basis of past experience, plans for distant benefits. H e would find the mentality which is normally capable of encompassing broad generalizations under the heading of brief abstractions, and which reaches out into distant space and time, reduced and limited to dealing with the concrete fact of providing for immediate needs. What is true of a state of emergency in a community of individuals is similarly true of that community of specialized groups of cells which make up the living body. In times of peace a large part of the energy of the adult animal is devoted to its own future security and to the perpetuation of its kind. All higher animals build nests and lairs, court and mate, rear their young, and play and rest. The large-brained civilized human being reaches out into the infinity of time and space, in order to provide greater security to his kind in ages to come. H e accumulates unmeasurable quantities of

THE

EMOTIONAL

STATE

23

wealth. Far more extensive than the most elaborate storehouses which he builds of wood and stone is the storehouse of his cerebral cortex, and in it he accumulates a quantity of provisions for future use far greater than that which is visible and palpable. If the tangible wealth which the human being has accumulated were destroyed, the knowledge which he has stored up in his cerebral cortex would rapidly recreate it ( 2 ) . But let an emergency arise which immediately threatens his life, and the work of providing for the future ceases, whether this be the accumulation of tangible wealth, or of that intangible treasure which consists of knowledge. H e must run with all speed from the course of the avalanche, and in the face of a charging beast he must either fight with the means at hand or escape. In a crisis which threatens his immediate destruction, man, as well as most of his cousins, therefore largely discards those functions which are devoted to distant benefits, the energies of the body being redistributed in such a manner that they flow toward the muscles. A l l the special organs of the body become divided into two classes j the skeletal muscles, which are directly engaged in overcoming the threatened external danger, and the rest of the organs, whose activity furnishes the muscles with energy-containing substances and the other means needed for their work. W h a t at first sight would impress an observer who could see the workings of the body in that state, would be the generally increased activity—the agitation or commotion of the living machinery of the body. Later he would discern a certain order in this heightened activity} instead of chaotic commotion, he would see orderly emotion. T h a t order will now be briefly sketched. T H E SUSPENSION OF C E R T A I N V I T A L A C T I V I T I E S IN T H E COURSE OF THE

EMOTIONS

T h e elaboration of means and the production of substances for future use largely ceases when the body is confronted with a situation which requires a large amount of muscular activity} that is, it ceases to the extent to which such activity is required. It has already been hinted that in relatively quiet states of the body a certain amount of surplus energy is employed in storing up in the cerebral cortex memories of experiences—knowledge—for future use, and that this activity is largely suspended in the emotional state. This proposition may appear to be inconsistent with certain facts and therefore requires an explanation.

24

THE

EMOTIONAL

STATE

Without anticipating too much of what will be said on this subject in the discussion of "The State of Attention" in Chapter X I I , it may be said here that the magnitude of an internal disturbance is by no means proportionate to that of the causative external disturbance. In this respect the animal body is indeed not very different from certain inanimate bodies. The application of a spark to gunpowder is an example. The great disproportion between the small force of the spark and the consequent explosion is due to the fact that the oxygen and the carbon in the compound being already in close proximity, it needs only a rise of temperature at one point for the whole to be set off. A large part of the cerebral cortex serves as a repository of memories of past experiences. The effect of an outside disturbance on the body depends on its past experiences with such a disturbance. If past experience is to the effect that a certain external disturbance is a signal of great harm or benefit to the body, a strong emotion of the vital capacities will take place, even though the disturbance may be slight j but if, on the contrary, past experience is to the effect that the external disturbance is fraught with neither benefit nor harm to the body, then, no matter how great the disturbance may be, the consequent emotion will be slight. When a house dog, upon hearing a certain barely audible sound from the outside, suddenly leaps up barking and scratching furiously at the door, exhibiting every mark of a violent emotion, we know that it is not merely the force of the auditory sensation which was the cause of the extreme agitation of the animal's vital capacities. The stock of the dog's experiences regarding the significance of the particular sound stored in his cerebral cortex has in this case set off the bodily energies, the sound from the outside acting like a spark on a magazine of gunpowder. The same is true of the man who becomes violently agitated by a mere whispered remark, accidentally overheard, or by a bundle of weak light rays impinging on his retina. It is not the actual force of the sound waves or the light waves, but the significance of the sound or the sight, as it is evaluated in the light of past experiences— a significance either of danger or of benefit—which results in the violent agitation of the man's vital capacities. On the other hand, an external disturbance of considerable magnitude may have little or no effect on the machinery of the emotions of the animal or the person, if that disturbance is devoid of any significance of benefit or harm. The sound of the master's hammer against the anvil may not be in the least disturbing to the dog who is resting peacefully in a corner of the

T H E

EMOTIONAL

STATE

25

blacksmith shop; and the person who is comfortably seated in an armchair before the fire may remain entirely indifferent to the roar of thunder, the flash of lightning, and the raging of the storm outside. In apparent contradiction to the foregoing is the fact that a strong display of the emotions may be initiated by a slight external disturbance, in the absence of the cerebral cortex, implying an absence of memories of experiences. A familiar example is the activity of emotional expression in the normal young infant, whose cerebral cortex is still immature and who in this respect is not very different from infants born with a large cerebral defect and from the animals whose cortex has been experimentally removed. A few infants, born with an extensive defect of the cerebral cortex—socalled acephalic infants—have survived for a variable period of time and their behavior has been described by careful observers. A striking feature of this behavior is its emotional character. One such infant, investigated by Edinger and Fischer (3) lived for about three years. The baby, though it hardly moved the first year, nevertheless exhibited an emotional behavior by low moans and distortions of the face, as if it were in pain. It cried, beginning with the second year. The behavior of idiots with large defects of the cerebral cortex has been described by a large number of investigators. Slight annoyances, which call forth no emotional behavior in normal persons, bring about in such idiots attacks of rage and fury. I have seen a large number of defective and retarded children in the Vanderbilt Clinic. They were either victims of birth injuries of the cerebrum, or of congenital anomalies of that organ, of different kinds. Among the prominent features of the behavior of these defectives were great restlessness and a violent emotional display upon small provocation. Some of these children were like wild beasts recently confined in cages. They moved continually and aimlessly to and fro about the room, picked up objects and dropped them repeatedly. The least interference with their movements was sufficient to bring about a furious emotional outburst. Only on very rare occasions was there a display of pleasurable emotion. In the course of many years' observation it became obvious that whatever the mechanism of the emotions and of the expression of the emotions, it was unrestrained in these children afflicted with a defect of the cerebral cortex. More directly demonstrative of the unrestrained activity of the "disagreeable" emotions in the absence of the cerebral cortex, is the experimental removal of the latter in animals. Goltz's (4) decorticated dogs and Dusser

26

THE

EMOTIONAL

STATE

de Barenne's ( 5 ) decorticated cats lived for a number of months. In the absence of the cerebral cortex these animals were, of course, blind, deaf, and generally without sensation. These animals exhibited a marked emotional behavior in response to slight disturbances, such as are ignored by normal animals. T h e pinching of the dog's skin, moving it from its cage, or scratching its back caused it to growl, bark, snarl, and snap. Merely lifting the cats made them growl and spit and caused their hair to become erected. Cannon and Britton ( 6 ) describe a strong emotional behavior of cats recovering from anesthesia, immediately after the operation for the removal of the cerebral cortex: When the operation is performed . . . there appears quite spontaneously a group of remarkable activities such as are visually associated with emotional excitement—a sort of sham rage. A complete list of these pseudaffective phenomena which we have observed is as follows: lashing of the tail; vigorous arching of the trunk, and thrusting and jerking of the limbs in the thongs which hold them to the animal board, combined with a display of claws in the forefeet and clawing actions, often persistent j rapid head movements from side to side with attempts to bitej very rapid panting respiration. . . . Besides the foregoing changes which involved skeletal muscle there were typical and more permanent visceral effects. Erection of the tail hairs, . . . sweating of the toe pads, . . . dilation of the pupil, . . . micturition . . . and a high blood pressure . . . [6, pp. 287-90]. [Further researches show that after these operations there was] . . . an abundant outpouring of adrenin, and an increase of blood sugar up to five times the normal concentration. This play of a "pseudaffective" state of sham rage might continue for two or three hours [7, p. 246]. O n the one hand, then, we find that a slight external disturbance is, through the mediation of the cerebral cortex, capable of evoking an emotional response out of all proportion to the actual magnitude of that disturbance. O n the other hand, we are confronted with the fact that a defect or complete absence of the cerebral cortex facilitates the display of the "disagreeable" emotions. These seemingly contradictory facts are reconcilable on the basis of the following considerations. It must be borne in mind that a cerebral cortex of the mammalian size and complexity is a rather late acquisition in the course of animal evolution. For countless ages a vast variety of animals, devoid of a cerebrum, lived and struggled more or less successfully for the maintenance of their

THE

EMOTIONAL

STATE

1"}

respective individualities and of their kinds. As a matter of fact most of the animals inhabiting the world today are entirely devoid of that organ. The invertebrate animals living now so far exceed in numbers the vertebrate forms, especially mammals, that the possession of a cerebral cortex, which is a prominent feature of the latter, must, from a biological point of view, be considered as an exception. The cerebral cortex is essentially a storehouse of memories of the experiences of the individual's lifetime. By means of his cortex man is able, besides, to appropriate indirectly the experiences of his predecessors and of his contemporaries. Not that the invertebrate animal, devoid of a cerebrum, has no memories of experiences j but such memories are manifested in the individual animal not as experiences of its own lifetime, but as those of a great number of its predecessors—in fact, the experiences of its species. Such an inherited record of experiences of many preceding generations is manifested by the animal's adaptation to the particular surrounding conditions within the limits of which it is able to live. Whatever store of memories of experiences such an individual animal is able to acquire, to retain, and to employ in a manner to facilitate its adaptation to somewhat different conditions from those which confronted its predecessors, is very small indeed as compared to that of the vertebrate animal possessed of a type of brain of which the cerebral cortex is a definite part. Notwithstanding the lack of a cerebral cortex and therefore of any considerable record of individual experiences, the invertebrate is able to cope with emergencies. The successful dodging of the mosquito from the hand which aims to destroy it, the sting of the wasp or of the bee which drives off the intruder and interloper, both testify to the existence in these cerebrumless animals of a mechanism for the concentration and redistribution of energies which enable them to overcome emergencies by an appropriate behavior. Among such animals, however, the life of the individual is entirely subservient to the life of its kind. They multiply with great rapidity, and the death of an individual is therefore of little consequence. From the human point of view the bee, in stinging, exhibits an astonishing degree of courage and self-sacrifice, for it runs the hazard of disemboweling itself after the act. Unlike ourselves, any threat of danger to its community is invariably met by an aggressive army of volunteers. The draft, which with us has been found to be the most effective way of marshaling able citizens for the protection of their community, is unknown among these insects. They never

28

THE

EMOTIONAL

STATE

dodge service. In this, as in most other respects, their behavior is largely fixed. From the point of view of survival of the species such prodigal selfsacrifice is, however, possible only under circumstances of an abundant supply of individuals. Among animals possessed of a cerebral cortex, who procreate scantily, the life of an individual is too precious to be readily surrendered. Gibbon (8) records the fact that at the time of his writing, in the latter part of the eighteenth century, the loss of the numbers of human beings who died in the plague which raged in the reign of Justinian in the latter part of the sixth century had not yet been restored. T h e coward or the conscientious objector is an expression of the biological need for the conservation of individuals in a species whose numbers must needs remain forever small. T h e behavior of the cerebrumless animal, lacking the ability to modify its reactions by means of a record of its individual past experiences, consists on the whole of a fixed pattern. The life of such animals consists of an almost undeviating routine. It is determined by the direction of the momentum imparted to it by its species, and any disturbance of that direction— of the status quo—endangering, as it must, the existence of the animal, is rectified by that concentration and redistribution of its bodily energies which corresponds to the emotional state of animals endowed with a cerebrum. And the same holds true of the animal whose cerebral cortex has been designedly removed. Its reactions cease to be modified by its past individual experiences, for the simple reason that with the loss of its cortex the animal has lost its record of past experiences. Its behavior then becomes like that of the animals whose adaptations are of a fixed kind, hardly any of which are acquired in the lifetime of the individual, nearly all of them being inherited. Its life is determined by the particular direction of the momentum imparted to it by its species; any disturbance of its course is therefore a nocuous disturbance which is overcome—"responded to"—by a corresponding change of direction of its bodily energies. It is such a change which is implied by the term emotion. Since any disturbance of the particular state of the moment of such an animal is a nocuous disturbance, the reason for the facility and uniformity— "the reflex-like regularity"—with which its emotional reactions of the "disagreeable" kind are elicited, becomes easily understandable. It is this latter fact which differentiates the activity of the emotions of the

THE

EMOTIONAL

STATE

29

animal in possession of a cerebral cortex from that of the acortical or the decorticated animal. The emotional reactions of the animal with a sound cerebral cortex vary in kind and intensity, and they are not regularly elicitable in response to a given disturbance. In such an animal the value of a given disturbance is appraised in the light of its past individual experiences as a signal either of harm or of benefit of a certain degree, to come either immediately or in the more or less distant future, or as having no special significance of any kind. An emotional reaction, therefore, may or may not follow. It will be shown later that the nerve apparatus which is concerned in the activities of the emotions is not the cerebral cortex, but certain older structures situated below it; and that the function of the cerebral cortex with relation to the emotions is to determine their kind and degree of intensity in correspondence with past experiences; and that once an emotion has been set going, it may continue largely without further participation of the cerebral cortex. In this sense the emotional reaction is possessed of a certain autonomy, for as we have seen, it can take place in the absence of the cerebral cortex. The behavior of the sound animal in a highly emotional state is thus similar to that of the decorticated animal. In this respect man is no exception. A number of popular expressions bearing on this state are illustrative of the relative freedom from cortical control which prevails during the sway of the organism by the strong emotions. " H e lost his head in his excitement," " I was so wrought up that I did not know what I was doing or saying," and other such expressions testify to the diminution of cortical control of behavior during the course of a strong emotion. As the accumulation of memories of experiences in the cerebral cortex proceeds from infancy and throughout life, the temporary loss of cortical control during the prevalence of an emotion amounts to a reversion of the person's or the animal's behavior to that of an earlier period of life. Stories similar to the one about the polite and polished prima donna, whose behavior reverts to her former status of fishwoman when her maid inadvertently spills the string of pearls on the floor, are familiar to everybody. They are pregnant with the truth that in the absence of cortical control during the strong emotions, past experiences are no longer brought to bear upon present behavior for the sake of future benefits—a reversion to the behavior of a period of life when the amount of experience stored up was meager.

30

THE

EMOTIONAL

STATE

T h e degree of facility with which emotional behavior is manifested may be said to be in inverse proportion to the degree of activity of cortical function—in inverse proportion to the degree to which past experiences control present behavior. T h e "sophisticated" members of an audience at the theater judge the performance in the light of their past experiences and are not, therefore, easily " m o v e d " to direct their bodily energies toward the skeletal musculature. T h e expression of the emotions by vociferous applause and in other ways comes from the younger, the less experienced contingents. T h e person who is easily " m o v e d " to expressions of joy or sorrow is not as a rule endowed to any high degree with the associative functions of the cerebral cortex. THE

A R R E S T OF DIGESTION

DURING A STRONG

EMOTION

The digestive process consists in the manufacture of substances to be used for the combustion and the repair of the body. The greatest amount of combustion takes place in the skeletal muscles. T h e process of digestion itself, however, involves a large amount of activity of the smooth musculature of the gastro-intestinal tract, and a very considerable proportion of the combustible substances elaborated by the process of digestion is therefore devoted to its own activity. If the body be likened to a gasoline-operated ship, which carries in its hold its own gasoline refinery, then it will be seen that outside of that used in propelling the ship, a certain amount of the combustible produced must be devoted to the operation of the refinery. There is in this respect another likeness of the living body to such a ship. T h e gasoline, as it issues from the refinery, is not immediately fed to the parts which operate either the propeller of the ship or the refinery engine, but is first stored in tanks, from which it is then drawn in the needed quantities. T h e living body has a similar arrangement. T h e combustible substances elaborated by the digestive tract are not immediately fed to the moving machinery, but are first stored in certain organs from which the substances are then drawn upon as they are needed. Should there occur an emergency which threatens the immediate destruction of the ship if it does not proceed with the utmost possible speed, and which therefore requires the consumption of an extraordinarily large quantity of gasoline, a wise captain would order the leads from the storage tanks to the refinery engines shut off for the time being. The refinery would then come to a standstill and the process of storing provisions for the more or

THE

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STATE

31

less distant future would cease for the time being. But the more abundant supply of gasoline available for the propeller engines might save the ship. So it is with the living body. T h e process of refinement by the digestive organs of energy-containing substances from the crude materials of food, for use in the more or less distant future, ceases in an emergency which requires an abundant supply of those substances for the skeletal muscles. A strong emotion prepares for such an emergency. T h e cessation of digestive activity during the strong emotions is a familiar fact. T h e keenest appetite for food vanishes at the announcement of sad or even of very j o y f u l news; and almost everybody has experienced the fact that a continued indulgence in food under these circumstances is followed by an attack of indigestion. T h e dry mouth, the aversion for food, and the chronic abdominal discomfort of the anxious, the sorrow-laden, the apprehensive, or the pain-ridden person are generally familiar facts. Experimental procedures are in this respect fully corroborative of common experience. T h e movements of almost the entire alimentary canal [says Cannon (7, pp. 13, 14)] are wholly stopped during great excitement. In my earliest observations on the movements of the stomach I had difficulty because in some animals the rings or waves of contraction were perfectly evident, while in others there was no sign of activity. Several weeks passed before I discovered that this difference was associated with a difference of sex. In order to be observed with Rontgen rays the animals were restrained in a holder. Although the holder was comfortable, the male cats, particularly the young males, were restive and excited on being fastened to it, and under these circumstances gastric peristaltic waves were absent; the female cats, especially if elderly, usually submitted with calmness to the restraint, and in them the waves had their normal occurrence. Once a female with kittens turned from her state of quiet contentment to one of apparent restless anxiety. The movements of the stomach immediately stopped, the gastric wall became wholly relaxed, and only after the animal had been petted and began to purr did the moving waves start again on their course. By covering the cat's mouth and nose with the fingers until a slight distress of breathing is produced, the stomach contractions can be stopped at will. In the cat, therefore, any sign of rage or fear . . . is accompanied by a total abolition of the movements of the stomach. Even indications of slight anxiety may be attended by complete absence of the churning waves. In a vigorous young male cat I have watched the stomach for more than an hour by means of the Rontgen rays, and during that time not the slightest beginning of peristaltic activity

3*

THE

E M O T I O N A L

STATE

appeared; yet the only visible indication of excitement in the animal was a continued quick switching of the tail to and fro. What is true of the cat I have found true also of the rabbit, dog and guinea pig—very mild emotional disturbances are attended by abolition of peristalsis. In accord with common experience and experimental procedure, clinical observation is to the effect that coincident with a strong emotion there is an arrest of the movements and of the glandular secretions of the digestive organs. Dunbar (9) has recently classified the clinical literature on the subject, and she records numerous experiences of physicians, expert in the field of gastroenterology, which are corroborative of the foregoing facts. Observations like those of Farr and Lueders ( 1 0 ) , with which every physician is familiar, are rather puzzling. These investigators record a number of instances of chronic indigestion, coincident with chronic states of depression. States of depression, however, would appear to be significant of a general inadequacy of the organism in surmounting obstacles, rather than as preparatory to intense muscular activity. T h e defect of the digestive functions in these cases cannot therefore be ascribed to a conservation of bodily energies for the purpose of any intensified activity of the skeletal musculature. But as we are still ignorant of the causes of such states of depression, they cannot be put down as invalidating the general proposition that in acute emotional states, such as call for intense muscular effort, one of the factors in the process of conserving the bodily energy for the benefit of skeletal muscular activity is an arrest of gastro-intestinal activity. I quote Cannon ( 7 , pp. 15, 16) further on this subject: There is no doubt [he says] that just as the secretory activity of the stomach is affected in a similar fashion in man and in lower animals, so likewise gastric and intestinal peristaltic waves are stopped in man as they are stopped in lower animals, by worry and anxiety and the stronger affective states. T h e conditions of mental discord may thus give rise to a sense of gastric inertia. For example, a patient described by Muller testified that anxiety was always accompanied by a feeling of weight, as if food remained in the stomach. Every addition of food caused an increase of the trouble. Strong emotional states in this instance led almost always to gastric distress, which persisted, according to the grade and the duration of the psychic disturbance, between a half hour and several days. The patient was not hysterical or neurasthenic, but a very sensitive woman deeply affected by moods. T h e feeling of heaviness in the stomach, mentioned in the foregoing case, is not uncommonly complained of by nervous persons, and may be due to stagna-

T H E

EMOTIONAL

STATE

33

tion of the contents. That such stagnation occurs is shown by the following instance. A refined and sensitive woman, who had had digestive difficulties, came with her husband to Boston to be examined. They went to a hotel for the night. T h e next morning the woman appeared at the consultant's office an hour after having eaten a test meal. An examination of the gastric contents revealed no free acid, no digestion of the test breakfast, and the presence of a considerable amount of the supper of the previous evening. T h e explanation of this stagnation of the food in the stomach came from the family doctor, who reported that the husband had made the visit to the city an occasion for becoming uncontrollably drunk, and that he had by his escapades given his wife a night of turbulent anxiety. T h e second morning, after the woman had had a good rest, the gastric contents were again examined; the proper acidity was found, and the test breakfast was being normally digested and discharged. These cases are merely illustrative and doubtless can be many times duplicated in the experience of any physician concerned largely with digestive disorders. Indeed the opinion has been expressed that many cases of gastric indigestion that come for treatment are functional in character and of nervous origin. It is the emotional element that seems most characteristic of the cases. T o so great an extent is this true that Rosenbach has suggested that as a term to characterize the cause of the disturbance, "emotional" dyspepsia is better than "nervous" dyspepsia. Studies have been made on human beings in whom the oesophagus had become closed as a result of disease, and they were fed through a fistula made in the stomach ( 7 ) . A s is well known, the sight or the smell of food induces the secretion of saliva—the familiar watering of the mouth. It is a phenomenon the significance of which will be discussed in Chapter V I I I , "Representation and Symbolism." In the patients with a closed oesophagus and a fistula in the stomach opening on the outside, it was observed that gastric juice as well as saliva was secreted at the sight or smell of food ( r i ) , when the patient was hungry. Bogen ( 1 2 ) observed a threeand-a-half year old child with oesophageal stenosis and gastric fistula. W h e n he talked to the nurse about the meat the child was to have, hydrochloric acid appeared in the stomach. I f , however, the patient became for any reason irritated or excited, the gastric secretion was arrested. Schrottenbach ( 1 3 ) observed two patients with complete stricture of the oesophagus and gastric fistula. H e found that disagreeable emotions abolished the effects of stimuli which usually result in an increase of gastric secretion in such cases. Parallel experimental procedures on animals ( 1 4 , 15) have shown that irritation or excitement, due either to the confinement of the animal

34

THE

EMOTIONAL

STATE

in a holder or to other causes, uniformly result in the arrest of gastric secretion. The first step in the conservation of energy-containing substances in the body for the use of the skeletal muscles preparatory to, or during, their intense activity, is therefore an inhibition of the activity of the smooth musculature of the digestive organs and an arrest of secretion of the digestive juices. The emotional state involves or is preparatory to such activity of the musculature. CHANGES IN T H E BLOOD SUGAR C O N T E N T IN EMOTIONAL

STATES

The essential energy-containing substance, whose combustion furnishes the power for muscular contractions, is blood sugar. It is stored in the liver in the compact form of animal starch—glycogen—and is released into the blood as sugar in needed quantities. As the living body, even when the muscles are relatively relaxed, is in a state of continuous combustion, the blood normally contains a certain slightly variable amount of sugar. When the blood sugar for any reason (as by the administration of an overdose of insulin) falls below a certain critical level, grave symptoms ensue—the candle flame flickers for want of tallow and threatens to become extinguished. If, on the other hand, the blood sugar for any reason rises above the average normal level and is not consumed rapidly enough by any increased muscular activity, a part of the excess passes through the filter of the kidneys and appears in the urine. In the course of intense muscular activity the amount of sugar released by the liver into the blood is in excess of that which is immediately needed by the muscles. Such an excess insures an abundant supply for continued muscular activity. When muscular activity is very violent, the excess of sugar in the blood becomes correspondingly immoderate and a part of it passes through the kidneys into the urine. As is the case in all instances of superabundance, there is thus a certain amount of waste. But a certain amount of waste as the result of a superabundant supply is, in the economy of the organism as in the economy of society, preferable to a hand-to-mouth existence which threatens a temporary interruption of activity, possibly resulting in permanent damage. One of the striking manifestations of the strong emotions is a release by the liver of increased quantities of sugar into the blood, and so great may be the excess of sugar in these conditions that it frequently appears in the

T H E

EMOTIONAL

STATE

35

urine. A reasonable interpretation of such increased liberation of sugar is a preparation for possibly needed muscular exertion. INCREASED S U P P L Y OF O X Y G E N DURING E M O T I O N A L STRESS

T h e increased combustion of sugar by the muscles necessitates a proportionately increased supply of oxygen. In correspondence with this fact, the rate and the depth of the respiratory movements in states of emotion are increased. E N H A N C E M E N T OF T H E C I R C U L A T O R Y A C T I V I T Y IN STATES OF E M O T I O N

Intensified muscular activity, implying as it does an increased rate of combustion, necessitates not only a larger supply of carbohydrate and oxygen but the removal of the products of combustion as well—mainly lactic acid and CO2—as fast as they are formed. T h e ashes and the smoke of the boiler furnace must be quickly removed or they will soon clog up the grate and choke the flames. T h e removal of the products of combustion is accomplished by the same means which expedite the utilization of sugar by the muscles—an enhanced transportation of materials. For the attainment of this end, the rate and strength of the heartbeat are increased in the emotions, even before muscular activity actually takes place. THE

REDISTRIBUTION

OF T H E

Q U A N T I T I E S OF BLOOD D E T E R M I N E D

TO

D I F F E R E N T PARTS OF T H E BODY IN T H E EMOTIONS

An increased supply of combustibles to and the removal of waste from the muscles during their intense activity is further facilitated by a redistribution of the quantities of blood which course through the different parts of the body. The smooth musculature surrounding the arteries of the digestive organs becomes contracted and their lumen is thereby narrowed, while the arteries supplying the active muscles become relaxed and expanded. The blood is thus squeezed out of the inactive organs and a larger supply of it is determined to the active muscles. PROVISIONS FOR T H E DISSIPATION OF E X C E S S T E M P E R A T U R E MUSCULAR

DURING

EXERTION

When the activity of the musculature becomes such that as a result of increased combustion the temperature of the body rises rapidly, the enhanced respiratory movements may not be sufficient to carry off all the

36

THE

EMOTIONAL

STATE

excess heat. Under these circumstances the blood vessels of the skin become dilated, the skin is reddened, and the blood, as it circulates near the surface, is cooled. Further provision for cooling the blood under these conditions is by the increased activity of the sweat glands. The excess of heat developed is thus carried off by evaporation from the moistened surface.1 INCREASE IN T H E N U M B E R OF R E D BLOOD CELLS DURING M U S C U L A R ACTIVITY

During muscular activity there takes place a contraction of the spleen, the storehouse of the red blood corpuscles, with the result that a greater number of these oxygen carriers is thrown into the circulation. T H E R E D U C T I O N OF T H E C O A G U L A T I O N - T I M E OF T H E BLOOD IN T H E STRONG EMOTIONS

The muscular activity of the emotional state is, from a biological point of view, one exercised by the animal in its fight for life; and fighting involves bodily injury and the shedding of blood. Animals which, when injured, bleed profusely, have in the long run fewer chances of survival. In the course of evolution, therefore, animals in whom the emotional state brought about a change in the composition of the blood such that upon its exposure to the air it coagulated rapidly, sealing the bleeding points, survived. The particular agency which leads to a faster coagulation of the blood in states of emotion will be considered later. D I M I N I S H E D FATIGABILITY OF T H E M U S C L E S IN T H E STRONG

EMOTIONS

It is common experience that muscular exertion which is accompanied by a strong emotion is more powerful and can be longer sustained than when it is the result of deliberation or when it is accompanied by a weak emotion. Pursued by a dog, a cat will execute leaps and bounds and will climb almost vertical surfaces with a degree of speed and agility of which it is incapable when its emotions are not aroused by the immediate danger. In the effort to save workers entombed by a mine accident, or a landslide, human beings have been known to sustain muscular effort continuously, without rest, for periods of time which would have been quite impossible for them had they not been sustained by the accompanying strong emotions natural under such 1 T h e cold sweat of "pale f e a r " cannot be accounted f o r on this basis and f o r the present remains unexplained.

THE

EMOTIONAL

STATE

37

circumstances. W h e n considering the particular agency which is immediately responsible for such an effect of the emotional state, we shall find that experimental procedure is in agreement with common observation. THE

GREATER

VIVIDNESS AND P E R M A N E N C E

EXPERIENCES

ASSOCIATED

WITH

OF T H E

EMOTIONAL

MEMORY

OF

STATES

It is a fact that experienes which are accompanied by strong emotions are remembered longer and are more vividly recalled than those accompanied by weak emotions—an important phenomenon which has not so far received the attention of physiologists, but which is well known to psychologists ( 1 6 ) . T h e reason for this will become clear from the discussion in Chapter X I I , " T h e State of Attention." T h e subject of the emotions, from the point of view of the question with which we are dealing, is subservient to an understanding of the conscious or informative state. T h e nerve apparatus concerned with the emotions, the expression of the emotions, and the subjective experience—the feelings—of the emotions will, therefore, be discussed in connection with the conscious state in the following two chapters. SUMMARY

1. T h e change which takes place in the body as a result of its collision with an outside force constitutes the physical basis of the emotions. T h e external manifestation of such bodily change constitutes the expression of an emotion. T h e mental index of this change is the feeling of an emotion. 2. T h e experience of sensation is informative of the specific internal disturbance produced by the collision of a given force with the body. Since, however, it is this disturbance which constitutes the physical basis of an emotion, it must be true that the sensory (or informative) state is inseparable from the emotional state. 3. T h e process of the bodily disturbance which constitutes a particular emotion consists essentially of a change in the direction of the bodily energies which corresponds in certain ways to the direction of the external colliding force. It is this change of the direction of the bodily energies which underlies the "response" of the body to the collision. 4. A part of the energy which highly evolved organisms absorb from the surroundings is stored for use in the relatively distant future. During the emotional state which underlies the "response" of the organism to a certain situation, the storage of energy for future use is diminished or suspended,

38

THE

EMOTIONAL

STATE

the available energy being utilized for purposes of the immediate "response." Thus the elaboration of food by the digestive organs for future use is suspended. 5. The cerebral cortex being a storehouse of memories for future use, its function is largely suspended in the course of the emotions. 6. The function of the cerebral cortex with relation to the rest of the body being the control of behavior in correspondence with past experiences, its effect on the emotions is either to enhance or to subdue them, according to the necessity of the occasion as determined in the light of past experiences. In the absence of the influence of the cerebral cortex, the emotions are uncontrolled, are initiated with facility, and are displayed with a high degree of intensity. 7. Owing to the fact that the adaptations of cerebrumless animals are not acquired by individual experience, but are inherited from their species, their behavior is characterized by a high degree of invariability. The course of such an animal's life is therefore largely predetermined by the history of its species. In the absence of any capacity for adaptation on the basis of individual experience, a deviation from its inherited course is fatal. Hence it is that any interference with the status quo of an animal which has been robbed of its individual experiences by the removal of its cerebral cortex, results in that redistribution of its energies for the rectification of its disturbed course which is equivalent to the emotional state. 8. Muscular acts which are accompanied by a strong emotion are the more energetic and can be the longer sustained. Psychologists are familiar with the fact that experiences which have evoked strong emotions are remembered better than those accompanied by weak emotions. REFERENCES 1 . Cannon, Walter B. T h e Wisdom of the Body. N e w Y o r k , W . W . Norton and Co.,

1932.

2. Mill, John Stuart. Principles of Political Economy.

1 8 4 8 . Chap. V ,

"Funda-

mental Propositions Respecting Capital." 3 . Edinger, L . , and B. Fischer. " E i n Mensch ohne Grosshirn." Pfliig. ges. Physiol., C L I I ( 1 9 1 3 ) ,

Arch.

f. ti-

535.

4. Goltz, F . " D e r Hund ohne Grosshirn." Pfliig.

Arch.

f. d. ges. Physiol.,

LI

( 1 8 9 2 ) , 570. 5. Barenne, Dusser de. "Recherches expérimentales sur les fonctions du système nerveux central, faites en particulier sur deux chats dont le neopallium avait été enlevé. Arch,

néerl. de fhysiol.,

IV (1920), 31.

6. Cannon, W . B., and S. W . Britton. "Studies on the Conditions of Activity in

THE

EMOTIONAL

STATE

39

Endocrine Glands. X V . PseudafFective Medulliadrenal Secretion." Atncr. Journ. Physiol., L X X I I ( 1 9 2 5 ) , 283. 7. Cannon, W a l t e r B. Bodily Changes in Pain, Hunger, Fear and Rage. N e w Y o r k , D . Appleton and C o . , 1 9 2 9 . 8. Gibbon, E d w a r d . Decline and Fall of the Roman Empire. 1 7 8 7 , Chap. X L I I I . 9. Dunbar, H . F . Emotions and Bodily Changes. A Survey of Literature on Psychosomatic Interrelationships, 1 9 1 0 - 1 9 3 3 . N e w Y o r k , Columbia University Press, 1935. 0. Farr, Clifford, B., and Charles W . Lueders. "Gastric Secretory Functions in the Psychoses." Arch, of Neur. and Psychiat., X ( 1 9 2 3 ) , 548. 1. Bickel, Adolf. "Experimentelle Untersuchungen über die Magensaftsekretion beim Menschen." Berliner klin. Wochenschr., X L I I I ( 1 9 0 6 ) , 845. 2. Bogen, H . "Experimentelle Untersuchungen über psychische und assoziative Magensaftsekretion beim M e n s c h e n . " Pflüg. Arch. f. d. ges. Physiol., C X V I I (1907),150. 3. Schrottenbach, Heinz. "Studien über den Einfluss der Grosshirntätigkeit auf die Magensaftsekretion des Menschen." Zeitschr. f. d. ges. Neur. u. Psychiat., L X I X ( 1 9 2 1 ) , 254. 4. Pavlov, J. P. T h e W o r k of the Digestive Glands. London, Charles Griffon and Co., 1902. 5. Bickel, A d o l f , and K . Sasaki. "Experimentelle Untersuchungen über den E i n fluss von A f f e k t e n auf die Magensaftsekretion." Deutsche med. Wochenschr., II (1905),1829. 6. Pülsbury, W . B. Attention. N e w Y o r k , T h e Macmillan C o . , 1908, p. 103.

CHAPTER

THREE

THE RELATION OF THE EMOTIONS TO THE CONSCIOUS, SENSORY, OR INFORMATIVE STATE A N A T O M I C AND P H Y S I O L O G I C

CONSIDERATIONS

We may arrive at a partial conception of the nature of the subjective experience of sensation by exploring the conditions under which a nerve impulse becomes a sensory impulse. A wider understanding of the nature of sensation may be gained in the later discussions of this work. It must be stated at the outset that the eyes, the ears, the taste buds, the touch corpuscles, and others of the class of organs known as sensory organs, are not, as a matter of fact, entirely sensory. They are receptors of disturbances in their surroundings outside and inside of the body. Disturbances, or changes in the surroundings, communicated to the receptors, set going nerve impulses along the nerves, which extend from these organs into the central nervous system—into the spinal cord, the brain stem, and the brain. A disturbance of the receptors, even though it be immediately followed by the obvious consequences of muscular and glandular activity, does not necessarily result in the subjective experience of sensation. The eyelids may close and the eyeballs move and the pupil may contract when a light enters the eye, without any sensation of light being experienced by the subject. A striking example of this fact is to be found in the powerful movements of the epileptic convulsion, in which the activity of the coordinating motor mechanisms of the lower portions of the central nervous system, set going by certain agencies, are kept up by the disturbance of the receptor organs known as muscle spindles, each stretch of a muscle being the cause of its following contraction. The nerve impulses set going by such a disturbance of the nerve receptors in the muscle are not productive, in the convulsed patient, of any sensation. The fact is that the nerve fibers which extend from the receptor organs branch out upon their entry into the central nervous system (fig. IA). By

Fig. i . A SCHEMA O F T H E LATERAL VIEW O F T H E CEREBROSPINAL A N D A U T O N O M I C NERVE SYSTEMS A. Afferent (entering) spinal nerve. B. Spinal ganglion. C. Sensory pathway. D. Thalamocortical nerves. E. Association systems. F. Corticospinal (pyramidal) pathway. G. Corticothalamic nerves. H. Thalmus. I. Hypothalamus. J . Lateral column of autonomic cells. K . Ventral column of motor cells to skeletal muscles. L. An intercalated nerve. M. Preganglionic of the upper autonomic. N. Postganglionic of the upper autonomic. O. Preganglionic of the middle autonomic. P. Postganglionic of the middle autonomic. Q. A motor nerve to the skeletal muscle. R. Visceral pathway from hypothalamus.

42

EMOTIONS

AND

CONSCIOUS

STATE

far the larger number of these branches come into contact with the motor cells, whose nerve fibers proceed to innervate either the skeletal muscles or the musculature of the visceral, vascular, or glandular organs. Nerve impulses which pass along these branches do not result in the subjective experience of sensation. A smaller number of branches extending from the receptor organs proceed, however, throughout the length of the spinal cord and the brain stem, and after a number of relays finally terminate in certain relatively small areas of the cerebral cortex. Only nerve impulses which proceed along these latter nerve branches may be productive of sensation, though they are not necessarily so. We shall see, indeed, in the course of this study (Chapter XII, "The State of Attention") that the experience of sensation, even when a nerve impulse passes along the nerve branches destined for the cerebral cortex, is rather an exceptional event, requiring certain special conditions for its occurrence. However, that only nerve impulses passing along these nerve branches are potent to produce the subjective experience of sensation is abundantly evidenced by a great number of facts. When, as not infrequently happens, the nerve pathway destined for the cerebral cortex is severed by disease, by accident, or by design, sensation disappears, although coordinated and apparently "purposeful" movement, in response to a disturbance imparted to the receptor organs, largely remains. Sensation is, therefore, in the first flace, a function of the cerebral cortex. T H E BIOLOGICAL S I G N I F I C A N C E O F T H E SENSORY S T A T E

SO subordinated are all the other functions of the human being to the sensory functions of his immensely developed cerebral cortex that, deprived of any of the sensations, he largely loses the capacity for executing a number of immediately necessary protective reactions. Deprived of temperature sense, for example, he may not withdraw his hand from a heated object in contact with it, and so may lose his hand. But a decapitated frog, deprived of all sensation, will withdraw its leg when its foot is pinched and, lacking the strength to free it from the offending hold, will even "attempt" to push it off with the other foot. Even in higher animals below man, the destruction of the cerebral cortex, or the severance of the spinal cord, with the consequent loss of all sensation below the level of the cut, does not entirely deprive them of a number of more or less appropriate reactions in response to disturbances imparted to their receptor organs. The truth of the last statement is corroborated by a very large number of ingenious experiments

EMOTIONS

AND

CONSCIOUS

STATE

43

and keen observations. The fact that a dog whose spinal cord has been severed at a high level will execute the remarkable scratching movements in response to a disturbance of the touch corpuscles which simulates the bite of a flea ( i ) , is illustrative of the efficiency of the machinery for muscular coordination of the lower central nervous system, in protecting the animal in the entire absence of any subjective sensory experiences. We have already seen that the "emotional" reactions are elicitable with even greater readiness in animals deprived of sensation by the removal of their cortex than in sound animals. Nor are instances of protective reactions in the relative absence of sensation lacking in man. The sleeping person who "attempts" to drive off a fly from his face either by movement of his facial muscles or by a motion of his hand and who, if the irritation persists, turns on the other side, or pulls the covers over his face, testifies upon awakening that he experienced no sensation either of the annoyance of the fly or of his own movements. Since every function of the living organism has been evolved as an adaptation to corresponding external conditions, it may naturally be asked: What can be the biological significance of the subjective experience of sensation, if the organism can execute movements appropriate to surrounding disturbances without any concomitant sensation? A consideration of the fact that in the course of evolution certain organs and functions develop at the expense of retardation, and even ultimate practical disappearance, of other organs and functions, further justifies the question regarding the significance of the sensory state. Witness, for example, the fact that animals which fly are generally poor runners; that the great development of those mental functions in man which are manifested in his employment of tools have resulted in proportionate loss of his muscular strength and agility j that animals which for one reason or another are short-lived, have greater powers of procreation than those which live relatively long. In the face of a non-sensory behavior which is more or less appropriate to surrounding conditions, is it not a legitimate speculation that a sensory behavior has evolved at the expense of a non-sensory one, but that a completely anesthetic yet highly appropriate behavior is possible? And if such behavior is possible, what are the reasons which have been operative for the evolution of sensory behavior in the so-called higher animals, so largely at the expense of nonsensory behavior? What are the essential advantages of a sensory organism over one which, lacking a cerebrum, is devoid of sensation?

44

EMOTIONS

AND

CONSCIOUS

STATE

An analogy, no matter how distant, will be of assistance to the approach of the problem. We can construct a machine which could respond to a certain number of disturbances in an appropriate manner, that is, in a manner to make it survive for a certain length of time. The automobile is a ready example. In a number of ways the automobile is as responsive to external conditions by appropriate internal changes as is the driver. It has, of course, its own particular way of doing so. By a different rate and a different amplitude of the vibrations of its different parts, it can furnish information, to one who understands that language, regarding a large number of details in the surfaceconformation and consistency of the roadbed. It responds to the temperature of the surroundings in a certain way. It is far more responsive than the driver on the point of quality of the combustibles which enable it to move. True, it cannot replenish the materials which it consumes nor can it repair or replace worn out or injured parts without human assistance, but neither can the driver. This difficulty, however, can be surmounted by the installation of special devices. It is a relatively simple matter to construct an appliance in connection with the machine by which it would stop in front of a filling station before its materials are quite exhausted and signal its wants to the attendant 5 or to stop in front of a machine shop and signal the mechanic its need for having a certain part repaired or replaced. We must of course accord to the automobile the same social advantages which are enjoyed by the driver. The latter is highly specialized; he can drive, but he can neither make his clothes nor bake his bread. In return for the useful service of driving, however, he obtains his clothes and his bread from the likewise specialized tailor and baker, by a process of fair exchange. So is our automobile highly specialized in the service of traction; and in return for carrying loads it obtains from the likewise specialized attendant at the filling station and from the mechanic the things which it needs. So far, then, the sensations which the driver subjectively experiences do not place him at an advantage over the machine which is devoid of all sensation. We must therefore follow their respective behaviors some distance further. The machine, having struck against an object on the road, has injured one of its parts. But the device we have installed helps out of the difficulty. It stops in front of a machine shop and has the injured part repaired or replaced. Traversing the same or a similar stretch of road, the automobile

EMOTIONS

AND

CONSCIOUS

STATE

45

once more strikes against an obstacle, again the same part is injured, and again is replaced. T h e same obstacle is encountered repeatedly and, its machinery remaining unchanged, it continues injuring the same part repeatedly and having it repeatedly replaced. Its multiple experiences do not change its behavior toward the particular obstacle. Each repeated experience is a totally new event, having no connection with similar preceding events and no bearing on similar future events. It is different in the case of the driver of an ordinary automobile. Having injured himself or his automobile by striking a certain obstacle, he will avoid it the next time. His experience with the obstacle has changed his behavior toward it. His present experiences are in some way influenced by his past experiences, and they have a bearing on his future behavior. His experiences, in other words, are in some way interconnected. This difference between the automobile with a number of devices, whose behavior is not modified by past experiences, and the driver whose behavior is modified by every experience, seems at first sight small, but gains increasing significance the more it is observed. The driver's manner of meeting succeeding exigencies being determined not only by the immediately preceding experience but by his past experiences of all kinds, his adjustment to changes in his surroundings increases with the passage of times as long as he is active. Such an increasing adjustment of the organism to the surroundings constitutes the process of learning—a capacity which the machine with its fixed devices, no matter how many such devices it may have, does not possess. W e shall see later that organisms very low in the animal scale exhibit changes in behavior as a result of immediately preceding experiences. Such changes are not, however, in the course of the individual's lifetime of a cumulative nature. Therefore, although these new modes of adaptation as a result of immediately preceding experience doubtless constitute the principle which underlies the process of learning, it is not the process of learning in the ordinary sense of the word. That the function of sensation is subservient to the cumulative process manifested in the increasing adaptation known as learning will become clear from a consideration of the bodily changes concomitant with sensory experiences. T H E N E R V E I M P U L S E — T H E COURSE OF T H E CEREBRAL N E R V E P A T H W A Y

Even a most superficial sketch of the anatomical course of the pathways traversed by nerve impulses from the receptors to the muscles, the glands,

EMOTIONS

46

AND

CONSCIOUS

STATE

and the other organs by the long way of the cerebral cortex, and of the physiological significance of this long and very devious nerve pathway, will prove to be of great assistance to a conception of the possible manner in which past experience influences present behavior. The branches of the nerves which extend from the receptors to the cerebral cortex are not continuous, but are interrupted at a number of points (fig. i c ) . The nerve pathway in question is, as a matter of fact, made up

A

B

Fig. 2. A C O M B U S T I B L E S T R I N G A N D A P A R A L L E L S C H E M A

OF

T H E A R R A N G E M E N T OF NERVES A . A combustible string from which a number of strings diverge and then converge upon a single string. B. A parallel schema of the arrangement of nerves.

of a number of nerves placed end to end, and the nerve impulses which traverse that pathway are relayed from nerve to nerve at their junctions. Generally speaking, the nerve impulse consists of a wave of metabolic change in the nerve, which in certain respects may be likened to a string saturated with a combustible substance and which, when ignited at one end, burns from point to point to the opposite end. The difference between such

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a string and a nerve is that the burned parts of the string are not restored, while in the case of the nerve impulse which involves succeeding parts of the nerve, the preceding parts are in a short time restored to their original state. It will be readily seen that if a number of combustible strings diverge from one point, a single spark at that point will set the process of combustion going along all the diverging strings, thus multiplying the energy of the original spark. On the other hand, if the number of diverging strings converge again at their opposite ends on a single string in the manner shown in the diagram (fig. 2 ) , the energy evolved by the combustion of that single string will not exceed in quantity that of any one of the strings converging on it. In this respect, too, the nerve differs from a string. The nerve impulse, it is true, may be communicated from one nerve to a number of diverging nerves and the total number of nerve impulses will thus be multiplied. But if a number of nerves converge again on a single nerve, the number of impulses traversing that one nerve may be equal to, or greater, or less than those traversing any one of the nerves converging on it. If the wave of the nerve impulse travels with equal velocity in all the converging nerves, then a number of such waves will be communicated at the same instant to the single nerve on which they converge. A number of sparks communicated to a single string at a single point at the same moment will not, however, cause the latter to burn any better than if it had been ignited by a single spark. And the same is true of a number of impulses communicated to a nerve at the same moment—they will be no more effective than if a single impulse had been communicated to it. The heat and flame of the string are determined by the amount and quality of combustible it contains and not by the magnitude of the spark which ignites it 5 and the same is true of the nerve. Since the nerve impulse, however, is in the nature of a wave, the nerve may be traversed in succession by a larger or smaller number of such waves within a given time. If the impulses in a number of nerves which converge on a single nerve traverse them at different rates of speed, which is most probable, we have the following possibilities: ( 1 ) a number of impulses will be communicated to the single nerve in rapid succession, and these will traverse it throughout its length; ( 2 ) some of the nerve impulses will be lost, either because they are communicated at the same moment or because, being too close together, the nerve is not sufficiently restored to its original state to conduct them; 1 ( 3 ) different nerves are pos1 In the language of nerve physiology, the impulses will arrive during the refractory of the nerve and will therefore be extinguished.

feriod

48

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sessed of different capacities for conducting nerve impulses under the same conditions, and the same nerve has different capacities for conduction under different conditions. T h e effect on a single nerve of a large number of nerve impulses, communicated from a number of nerves converging upon it, therefore varies greatly. As the several relay stations (synapses), where some nerves terminate and from which others arise, are points where a number of nerve branches converge on one nerve and where the branches of a single nerve diverge to communicate with a number of other nerves, they are for that and for other reasons to be pointed out later, places where great changes in the progress of nerve impulses are particularly apt to occur. THE

THALAMUS

T h e last and largest such relay station of the nerve pathways which extend from the receptor organs to the cerebral cortex is of especial interest. T h e connections which are established in this relay station between different parts of the nervous system have not yet been thoroughly explored. Suffice it to say here that the relay station in question consists of a vastly complex aggregation of nerve cells and nerve fibers. It is known in anatomy by the name thalamus. Certain subsidiary aggregates of nerve cells and fibers in connection with the thalamus, situated beneath and behind it, are known by the names subthalamus and hypothalamus (figs, i , 11, and 1 2 ) . The nerve fibers which convey sensory impulses from the receptor organs end in branches in connection with a number of cells in the thalamus. Some of these cells, in their turn, send out nerve branches which end in certain small areas in the cerebral cortex. Other branches of these cells, however, establish communication with cell groups in the subthalamus and the hypothalamus ; and the cells of the latter send out nerve fibers which are connected with the complicated system of nerves and nerve relay stations which innervate the blood vessels of the entire body, all the glands, and all the internal organs. I t is this latter system of nerves which is immediately responsible for the bodily changes which take place in the emotions. W e must glance, though ever so briefly, at the general arrangement of this nerve system. THE

CEREBROSPINAL

AND T H E

AUTONOMIC

NERVE

SYSTEMS

(FIG.

I)

T h e motor nerve cells, which are grouped in the two ventrally placed columns, one on each side, throughout the length of the spinal cord (fig.

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49

i k ) are in contact with the endings of nerve fibers which have their origin in the cerebral cortex (fig. i f ) . Impulses originating in the cerebral cortex can, by such an anatomical arrangement, be brought to bear directly on these motor nerve cells. As the nerve fibers which extend from these cells leave the spinal cord and pass without interruption to innervate the skeletal muscles, the activity of the latter is therefore more or less directly under the control of the cerebral cortex. Corresponding groups of motor nerve cells, for the innervation of the muscles about the head, are situated in the brain stem, and these, being likewise played upon by endings of nerve fibers descending from the cerebral cortex, are likewise directly influenced by the latter. The entire system of these nerves which innervate the skeletal and head musculature is known as the cerebrospinal motor nerve system. There are two other columns of motor nerve cells, one on each side throughout the length of the spinal cord, placed more laterally (fig. i j ) . Unlike the ventrally placed motor cells, these are not directly played upon by impulses from the cerebral cortex and they are not therefore directly under its control. We shall see, however, that indirectly the cerebral cortex does exert an influence over them. Two similar groups of such cells, one on each side, are found in the brain stem. The nerve fibers which extend from these cells leave the spinal cord and the brain stem to innervate the internal organs, the blood vessels, the glands, the hair muscles, and the iris of the eye. For the reason that this nerve system is not under the direct control of the cerebral cortex, it is known as the autonomic nerve system. Unlike the cerebrospinal motor nerves, the fibers of the autonomic nerve system do not pass directly from their cells of origin in the central nervous system to the organs which they innervate, but are interrupted in groups of nerve cells—ganglia—situated outside the central nervous system. The nerve cells contained in these ganglia, in their turn, send out nerve fibers, and it is the latter which pass to the organs which they innervate. The nerves of the autonomic system, which extend between the central nervous system and the ganglion cells outside of it, are conveniently termed preganglionic, while the nerves which extend between the ganglion cells and the organs which they innervate are distinguished as postganglionic. There are other differences between the cerebrospinal and the autonomic motor nerve systems. The cerebrospinal motor nerves have the same function throughout, and their general relation to the muscles which they in-

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nervate is throughout of the same order. The relation of the autonomic motor nerves to the organs which they innervate differs in different parts of the body and so does their function. T H E T H R E E DIVISIONS OF T H E A U T O N O M I C N E R V E S Y S T E M

The groups of nerve cells—the ganglia—of the middle part2 of the autonomic nerve system are placed immediately in front of the thoracic and lumbar portions of the spinal column (fig. i ) . Their preganglionic nerve fibers are therefore relatively short} while the nerve fibers which extend from the ganglion cells to the parts which they innervate—the postganglionic fibers—are relatively long. As this part of the autonomic system innervates not only the internal organs but the smooth musculature of the blood vessels, of the hair follicles, and of the glands of the skin as well, it will be readily seen that some of the postganglionic nerve fibers extend for a long distance—the entire distance from the thoracic and lumbar regions to the ends of the fingers and the toes. A very important point is that the preganglionic fibers of this middle portion of the autonomic system, although on the whole relatively short, differ greatly in length. The fact is that these nerves, upon leaving the spinal cord, branch out to enter not one ganglion, but from six to nine ganglia, up and down the series in front of the thoracic and lumbar regions of the spinal column. As each of these ganglia sends postganglionic nerve fibers for the innervation of each of a number of organs, it is obvious that nerve impulses proceeding along any one of the preganglionic nerves are capable of producing widespread effects. Almost exactly the opposite is the case with the parts of the autonomic nervous system which lie above and below (in front and behind in fourfooted animals) the middle division—the cranial and the sacral divisions respectively. The ganglia of the latter two portions are placed near or within the organs which they innervate, and their preganglionic nerves are therefore long, while the postganglionic are relatively short. The physiological significance of such an anatomical arrangement is that the action is limited to certain organs or to parts of organs. The innervation of the skeletal muscles by the cerebrospinal system for 2 Throughout the literature on the autonomic nervous system this part is termed the sympathetic system—an old and misleading term which it seemed to me best to discard. As this part of the autonomic system is situated between the cranial and the sacral divisions, I have called it simply the middle or the mid-autonomic, or the mid-division of the autonomic system,

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$I

the production of movement is such that while a muscle on one side of a joint contracts and shortens, that on the opposite side of the joint relaxes and lengthens. T h i s is the "reciprocal innervation of antagonistic muscles" elucidated by Sherrington ( 2 ) . A similar relation exists in the innervation of the viscera by the different divisions of the autonomic system to be described below. T H E C O O P E R A T I V E R E C I P R O C A L A C T I O N OF T H E A N T A G O N I S T I C DIVISIONS OF T H E A U T O N O M I C

SYSTEM

Most of the internal organs are innervated by two divisions of the autonomic nerve system, either by the middle and the cranial or by the middle and the sacral. T h e cranial division of the autonomic system contracts the pupil of the eye, the middle autonomic dilates it; and to the extent that one is active, the other is inactive. For example, while the cranial autonomic protects the retina in a bright light by narrowing the pupil, the mid-autonomic, whose function is to dilate the pupil, is inactive at the time; in a dim light the activity of the mid-autonomic, by dilating the pupil, admits more light into the eye, while the cranial autonomic, whose effect on the pupil is the opposite, remains inactive. It must be noted here that whatever amount of control is indirectly exercised by the cerebral cortex on the autonomic system, it appears to be greater on the upper and the lower (the cranial and the sacral) than on the middivision. T h e relative inactivity of the cerebral cortex in the course of strong emotions has already been noted; in agreement with this fact we find a manifestation of the inactivity of the cranial division of the autonomic system when the pupil is dilated in states of fear, rage, and the other strong emotions. W e can only speculate that such a dilation of the pupil in emotional states is an automatic provision for the better appraisal of the external object causative of the emotional state. T h e dilated pupil of the epileptic coma, when the function of the cerebral cortex is suspended, further corroborates the assumption of a greater autonomy of the middle than of the cranial division of the autonomic system. 3 A n example of a similar influence of the cerebral cortex on the sacral division of the autonomic system is given in the summary at the end of this chapter. 8 Unless, h o w e v e r , special causes can be assigned f o r the contracted pupils o f normal deep sleep, w h e n the f u n c t i o n o f the cerebral cortex is very largely suspended, the f o r e g o i n g assumption rests on rather thin i c e ; and no valid causes f o r the contracted pupils o f normal sleep have thus f a r been advanced.

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T h e cranial autonomic dilates the blood vessels of the salivary glands and causes a secretion of saliva; the mid-autonomic, by its action on the smooth musculature of the blood vessels, contracts them and narrows their lumen. T h e assumption of a greater control exercised by the cerebral cortex on the cranial than on the mid-division of the autonomic system is further corroborated by the function of the salivary glands. T h e sensory experience of the sight or smell of food, or of certain sounds associated with food, such as the mention of certain articles of food, or the ringing of the dinner bell—stimuli which become effective only through the mediation of the cerebral cortex—initiate, by the activity of the cranial autonomic, the secretion of saliva. O n the contrary, in the emotions of fear, of anxiety, of rage, and even of intense j o y , when the cerebral cortex is relatively inactive, the mid-autonomic sways the field, arresting or retarding the secretion of saliva with the production of the dry mouth and throat characteristic of those conditions. T h e cranial autonomic inhibits the function of the heart so that the rate of its beat is diminished. T h e middle division of that nerve system causes an acceleration of the heartbeat. In this respect, too, the greater control exercised by the cerebral cortex over the cranial than over the mid-division of the autonomic system is indirectly manifested by the incompatibility of the sensory activity of the cerebral cortex with the bodily states characterized by an acceleration of the heartbeat, such as violent muscular exercise ( 3 ) and the strong emotions. T h e cranial autonomic system, by its action on the smooth musculature of the stomach and the small intestine, causes the wavelike contractions of these organs, and by its action on the glands, the secretion of the digestive juices. T h e action of the mid-autonomic, on the contrary, is to relax the smooth musculature of these organs and to arrest their secretions. T h e sacral is related to the mid-division of the autonomic system in the same manner that the cranial division is related to it. T h e sacral autonomic innervates the colon and the lower part of the bowel, the bladder, and the internal organs of generation, causing the smooth musculature of these organs to contract and thus empty their contents; while the mid-division, by its inhibitory action on these organs, controls and directs the waves of contraction. T h e mid-autonomic, by its innervation of the liver, causes that organ to release sugar from its storehouse of glycogen. T h e action of the mid-autonomic on the spleen is to contract it and so squeeze out into the blood stream

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numbers of red corpuscles contained in that organ. T h e natural stimuli which have these effects on the mid-autonomic nerve system are exposure to cold, muscular exercise, oxygen-deprivation, and the emotions. T h e mid-division of the autonomic system exerts a tonic function upon the blood vessels of the entire body. By a graded contraction of the smooth muscles which surround them, the blood vessels are rendered elastic, the blood pressure is regulated, and the requisite amount of blood is determined to each of the several organs at any one time. Arteries which show only a slight increase of tone [says Hess ( 4 ) ] , or none at all, undergo a passive dilation and the flow of blood to the corresponding organs is accordingly increased. . . . It is thus possible to see how constriction here, passive widening there and active dilation elsewhere, together constitute a common act which produces a characteristic change in the blood distribution over the whole body. Great as is the amount of independence of the mid-autonomic system, it is, however, not entirely outside the control of the cerebral cortex. T h i s is exemplified by such phenomena as the local paralysis of the mid-autonomic nerves, manifested by the blush on the face of the young person at the thought of having been detected in the commission, or the desired commission, of an unconventional act. N o r must it be thought that the action of this division of the autonomic system is in such a case limited to the dilation of the blood vessels in the skin of the face and neck. T h e latter is but an index of its simultaneous widespread activity. A closer examination will, in such a case, disclose the fact that simultaneously with the local paralysis of mid-autonomic nerves in the blood vessels of the face, there is a stimulation of those parts of this nerve system which innervate the heart, the lungs, and other organs, as manifested by the acceleration of the cardiac and respiratory movements. I f , in the milder grades of this condition, other effects have not been discovered, the reason is that so far they have not been successfully investigated. But as the rapid heartbeat, the increased oxygenation of the blood, and the increased liberation of CO2 by the accelerated respiratory movements all subserve the ends of muscular activity (e.g., the trembling in extreme cases), we may be certain that an increased quantity of sugar is liberated by the liver and that the activity of the mid-autonomic division is manifested in still other ways. This division of the autonomic system innervates the sweat glands and the small muscles attached to the hairs covering the skin. T h e occurrence

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of sweating and of the erection of the hair in strong emotions and in sundry other conditions of the body is due to the activity of this nerve system. As has been said above, the autonomic nerve pathways which extend between the central nervous system and the organs which they innervate are interrupted in a series of ganglia which lie outside the central nervous system. In other words, each such pathway consists of two nerves placed end to end, and it is the secondary, that is, the postganglionic nerve, which innervates the organ. T o this rule there is one exception—the adrenal medulla. The latter is innervated by the primary, the preganglionic, nerve. Embryologic studies have disclosed the fact that the tissue of the adrenal medulla in the young fetus originates from the same masses of cells which are later differentiated into the autonomic nerve ganglia ( 5 ) . T h e tissue of the adrenal medulla is thus genetically related to the autonomic ganglion cells, and we shall presently see that its function is in many respects similar to that of the postganglionic nerves. T h e adrenal medulla secretes into the blood a substance known as adrenin, in quantities which are proportionate to the degree of muscular exertion, to the intensity of an emotion, to the degree of painful stimulation, to the extent of oxygen-deprivation, to the degree of exposure to cold, and to other conditions which set going the activity of the mid-division of the autonomic system. T h e presence of adrenin in the blood reinforces the action of the mid-autonomic nerves in activating the liver to release quantities of sugar. Like the mid-autonomic nerve system, adrenin inhibits the movements and the secretions of the gastro-intestinal tract, raises the blood pressure by a contraction of the arterial walls, and during muscular exercise contracts the blood vessels of the viscera and relaxes those of the muscles, thus determining a larger blood flow to the latter. Like the mid-autonomic, furthermore, it dilates the bronchioles, in conditions requiring an increased ventilation of the lungs; it causes an increase of the cardiac and respiratory rates; it contracts the spleen, with the result of an increase in the number of red corpuscles in the blood; and it dilates the pupil. The secretion of the adrenal medulla, itself set going by the action of the mid-autonomic system, reinforces the latter in every respect except one— it has no effect on the sweat glands; it also affects the skeletal musculature in a way to reduce its fatigue; and it increases the coagulation of the blood. Adrenin begins to be secreted a few minutes after the stimulation of the mid-autonomic nerves has initiated the characteristic vital activities of

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the body, and it continues for some time after the action of the former has ceased. Since the substance in question circulates in the blood, its effects are widespread throughout the body. 4 THE

S A M E A C T I O N OF T H E A U T O N O M I C

SYSTEM

IN D I F F E R E N T

BODILY

STATES

T h e dilation of the blood vessels of the internal organs and the simultaneous constriction of the superficial blood vessels which is productive of pallor of the skin, alike characterize the bodily states of exposure to cold, of fear, and of pain. T h e constriction of the visceral blood vessels, with the simultaneous dilation of the blood vessels of the skin and an outpouring of sweat, are alike characteristic of anger, of exposure to a high temperature, and of irritation of the skin by certain chemicals. A n arrest of the activity of the digestive organs is a characteristic of such different states as pain, j o y , sorrow, rage, fear, and asphyxiation. From what we know regarding the conditions which are necessary for * A discussion o f the effects o f acetylcholine, esterase, sympathin, and so f o r t h , w o u l d lead us too f a r afield f r o m our subject. T h o s e interested in this special subject are ref e r r e d to C h a p t e r I X , " T h e C h e m i c a l Transmission at N e r v e E n d i n g s , " in Evans' Recent Advances in Physiology, 1 9 3 6 ; also " H u m a n A u t o n o m i c P h a r m a c o l o g y , " I V , V I I , X I I , X V I ; and " P h y s i o l o g i c E f f e c t s o f A c e t y l - B e t a - M e t h y l c h o l i n e ( M e c h o l y l ) and Its Relationship to O t h e r D r u g s A f f e c t i n g the A u t o n o m i c N e r v o u s S y s t e m " ( 6 , 7 , 8, 9, 1 0 ) , by M y e r s o n and his coworkers. T h e f o l l o w i n g diagram (fig. 3 ) taken f r o m M y e r s o n ' s " H u m a n A u t o n o m i c

SYMPATHETIC

PARASYMPATHETIC

ADRENALIN BENZEDRIN

Fig.

3. A

SCHEMA AUTONOMIC

FROM

A.

MEYERSON'S

PHARMACOLOGY,

HUMAN

XII

P h a r m a c o l o g y , " Journ. A. M. A., C X ( 1 9 3 8 ) , 1 0 1 , furnishes an idea o f the c o m p l e x i t y and the importance o f the subject.

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muscular activity, we may argue that inasmuch as the different bodily states mentioned are either the accompaniments or the precursors of muscular activity, the same action of the autonomic system must underlie all of them. But as the same cause can be productive of different effects only when operating on different factors, we are still confronted by the question: W h a t are the factors which make for different bodily states under the same action of the autonomic system? The activities of the visceral and the vascular organs, in their relation to the movements of the animal, are comparable to the relation of a boiler and its furnace to the movements of the machine which it activates. A machine may be capable of a great variety of movements, but no matter what the movements may be, the pressure of the steam in the boiler must be adequate and there must be a dependable supply of combustibles in the furnace. Given an adequate steam pressure, the effects produced by the machine will then depend upon the particular type of machine and upon the materials furnished it. If the machine is of a fixed pattern and the materials furnished it are always the same, then the effects will be uniformly the same. Another type of machine is one whose pattern can be changed at will, so that it will punch out either round or square holes or intricate designs, according as the wheel which carries the dies is turned one or two or more notches. A machine may be of a fixed type, but if the materials on which it works are from time to time different, the ultimate effects will be different. Thus, for example, the steam in the boiler may operate an electric generator which furnishes an electric current to an electrolytic solution. Depending upon a change of chemicals in the solution, the objects suspended in it may become coated now with silver, now with copper, now with gold. The animal body is a combination of the latter two types of machine. THE

L O C A L A C T I V I T I E S OF T H E A U T O N O M I C

SYSTEM

W e have seen that the cells which give rise to the nerve fibers of the autonomic system are placed in two columns, one on each side of the spinal cord and the brain stem. This is an anatomic arrangement much like that of the nerve cells which give rise to the motor nerve fibers which innervate the skeletal muscles. In either case the cells up and down the columns are interconnected, in a great variety of ways, by special nerve cells and fibers. A vast number of laboratory and clinical observations point to the fact that

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such an anatomical arrangement is a provision for limited as well as for widespread activity. In the case of the neuromuscular cerebrospinal system, a reflex is mediated by three nerve elements: ( i ) A receptor organ in the skin, the mucous membrane, or in the muscle and the nerve which extends from it to the central nervous system; ( 2 ) one or more intercalated nerves; ( 3 ) one or more nerve cells and the nerve fibers which extend from them without further interruption to the skeletal muscles. Stimulation of the receptor organ is thus capable of producing reflex movement or the inhibition of movement of a variable number of muscles, with the production of simple localized or very complex and widespread movements. In the case of the autonomic system, simple and localized, or highly complex and widespread effects are likewise possible through the mediation of four nerve elements: ( 1 ) A receptor organ and the nerve which extends from it to the central nervous system; ( 2 ) one or more intercalated nerves; (3) motor cells (situated laterally in the spinal cord, and in the floor of the fourth ventricle in the brain stem) and the preganglionic nerve fibers which extend from them to the autonomic ganglia; ( 4 ) postganglionic nerve cells and fibers to parts of the vital machinery which they innervate. Local and limited, or diffuse and widespread activity of the vital machinery is thus made possible. Instances exemplifying the local activities of the autonomic system are many and various, and a number of them are familiar in everyday life. Everybody is familiar with the fact that rubbing or pressure on the skin is productive of localized redness—a paralysis of mid-autonomic nerves supplying the blood vessels of that part. Localized swelling, as a result of irritation of a part of the skin, is a common occurrence. E v e r y physician has seen patients who, although otherwise quite normal persons, suffer from the temporary inconvenience of localized oedema of the skin of the hands upon their exposure to cold, especially to cold water. T h e writer has seen persons whose skin, after a few seconds under a cold shower, became covered with goose flesh (due to stimulation of the mid-autonomic nerves which supply the hair muscles), accompanied by sensations of thickness, itching, and tingling. If the hands or the feet alone were immersed in cold water, those parts alone became affected in the way described. T h e attack persisted for a few minutes after the parts had been dried and warmed. Such instances are illustrative of the local as well as the general activity of the mid-autonomic system.

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Among the most distressing effects of abnormal stimulation of the midautonomic system by agencies which so far remain unknown, are two diseases, Raynaud's disease and thromboangiitis obliterans. The essential pathology of these two diseases consists of a spasm of the arterioles of the extremities. The spasm comes in recurring attacks, during which, the blood supply of the part being shut off by the constricted arterioles, the part becomes blanched. I f the attack is sufficiently prolonged, the part—a finger, a toe, or an entire limb—dies. That these conditions are brought about through the mediation of the mid-autonomic system has been amply demonstrated by the measures aimed at their arrest. Brown and Adson ( 1 1 ) and others describe the extirpation of the mid-autonomic ganglia or the severance of the preganglionic nerves as surgical measures for the arrest of these diseases. Following such operations, the patients are subject to certain inconveniences. They do not sweat in the parts of the skin supplied by the mid-autonomic nerves which have been severed; the skin innervated by these nerves becomes dry; the absence of goose flesh—the erection of the small hairs— can hardly be considered an inconvenience. Cannon, Lewis, and Britton ( 1 2 ) have extirpated in cats the entire chain of the mid-autonomic ganglia. These cats continued to live. But they were at a disadvantage under conditions of stress. They could not maintain a constant body temperature; before a barking dog they exhibited, it is true, some of the external expressions of their mental state of fear and anger. But the lack of the mid-autonomic nerve system deprived them of the effective equipment for aggression or defense. Their hair did not become erected, their blood sugar did not rise, increased quantities of adrenin were not poured into the blood. Their skeletal muscles could not, therefore, be mobilized for fighting. A critical consideration of the conditions under which human beings or animals, deprived of the mid-autonomic nerve system, were able to survive will, however, hardly support the conclusion that that nerve system is not indispensable to life. For it must be obvious that the defect of the human beings and of the animals who lacked the mid-autonomic system was supplied, under the artificial conditions of human society, by human beings whose mid-autonomic nervous systems were sound. In a state of nature the human being or the animal who cannot, when the occasion calls for it, mobilize the vital resources, must quickly perish. Prominent among the local manifestations of the activity of the midautonomic system is localized sweating. A number of normal persons are

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afflicted with sweating of the palms of the hands. T h e ingestion of pungent condiments brings out sweat on the forehead, the nose, and the upper lip in a number of persons. T h e forehead sweats more in muscular exercise and in hot weather than do other exposed parts. T h e biblical injunction " I n the sweat of thy brow shalt thou eat thy bread" is illustrative of this local activity of the mid-autonomic system. One of the most remarkable manifestations of the local action of the midautonomic system is that of blushing, already alluded to. Although the phenomenon is apparently limited to the face, or to the face, neck, and upper chest, it is found upon closer examination to be an exceedingly complicated reflex, exemplifying a high degree of cooperation of the cerebral cortex with the entire autonomic system. T h e existence of this reflex introduces an incongruity in our ideas of the evolution of the protective functions. T h e fact that the eyelids should wink automatically as a protective measure, wiping the conjunctiva clean of dust; that the sleeping person, largely unconscious, should automatically execute movements appropriate to the act of driving off a fly from his face; that the hairs or feathers of the body should automatically become erected as a protective measure against the action of cold ( 1 3 ) , or in order to make the animal's appearance more formidable to its enemy ( 3 ) ; and the existence of a large number of other such automatisms, is interpretable on the basis that their persistence has tended to the survival of the organism. But the involuntary act of blushing automatically betrays the young offender against society. One might argue that such automatic self-betrayal tends to the elimination of the offender and therefore to the survival of society. But in view of the fact that the unblushing liar or criminal is a greater danger to society than the blushing youth, the phenomenon is for the present inexplicable on this basis. T H E O S C I L L A T I N G B A L A N C E OF T H E BODY

W e r e the body merely a machine in which the motive power, represented by the autonomic nervous system, would be capable of the permutations and combinations of a given number of different degrees of local activities, we should for this reason alone have a great variety of internal conditions which could find expression in an equally large variety of external appearances. A s a matter of fact, however, the living body, while maintaining on the whole a certain constancy of pattern, changes from time to time in a great number of ways. In this respect it is like a complex balance which, while it maintains a general constancy of design, oscillates continually. It is,

6o

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moreover, a balance which changes in size and from time to time in function. The changes incident to the animal's growth, maturation, and decay speak for a continual alteration not merely in the size, but in the gross and minute design of the body. Certain organs mature or decay long before others. With the exercise of certain functions, and under the impact of environmental forces, gross differences of different parts of the body become manifest from time to time. Certain muscles become hard and bulging and the bones to which they are attached exhibit ridges and protuberances, while other muscles remain soft and small and their bony attachments inconspicuous. Underlying such changes in the gross and minute structure of the body are corresponding changes in the basic motive mechanisms—the vital organs and the autonomic nervous system which activates those organs. T h e assumption of qualitatively new functions by the boiler and the furnace bears the necessary implication of a change of some kind in their structure. T h e maturation of the sexual function, the menstrual cycle, the advent of lactation and of other functions, start going a new ebb and flow of certain processes in the autonomic nervous system; and although, with the means at present at our disposal, the particular changes in its structure which make possible the particular new activities defy investigation, the reasonable assumption is that permanent changes of some kind in its minute structure must take place from time to time. Grossly speaking, the living body may therefore be likened to a machine which, being capable of combinations and permutations of a number of fixed local activities, is, in addition to that, subject to changes in its structural and functional pattern. A somewhat closer view of the living body reveals the fact that no part of that machine is in a state of equilibrium for any appreciable length of time. The widespread effects of the substance adrenin, secreted into the blood in greater or less quantity by the adrenal medulla, have already been noted. From what has been said regarding the extirpation of the ganglia of the mid-autonomic system, it will be surmised that although the secretion of adrenin is conducive to a vigorous appropriate response of the body to certain surrounding conditions, it is not absolutely essential to life under the artificial conditions of human society. But the destruction of the adrenal cortex, either experimentally in animals, or by disease in man, is fatal. W e are still ignorant of the manner in which the secretion of the adrenal cortex operates so as to make it indispensable to life. T h e substances thrown into the blood by certain other glands of internal secretion are equally indis-

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pensable. The parathyroid gland secretes a substance which maintains a certain normal level of calcium in the body. Its removal in animals results in tetanic muscular contractions and death. The thyroid gland secretes a substance whose effect is to activate all the functions of the body. An absence or a diminution of the secretion of the thyroid gland results in cretinism— a condition characterized by mental dullness, an oedematous skin, a low metabolic rate, and general retardation of development. An oversecretion of thyroid substance results in a high metabolic rate, a rapid and weak heartbeat, a protrusion of the eyeballs, a mental state of restlessness, excitement, and anxiety, and death. A diminished secretion of the insular cells of the pancreas results in an excess of sugar in the blood and the other familiar symptoms of diabetes j an excess of insular substance in the blood (as by the injection of insulin) brings about a state of general collapse— pallor, sweating, weakness, convulsions, and death. A score or more of different abnormal bodily and mental states result from disorders of the pituitary gland. The absence of certain substances in the body produced by the sexual glands is followed by a disappearance of the secondary sex characters; and many mental and physical abnormalities are ascribed, by a number of investigators in that field, to disorders of that secretion. The foregoing examples will suffice for a reasonable surmise that an exact and continuous balance between the chemical substances contributed to the body, even by its own internal factories for their production, is hardly likely. On the average, a so-called normal balance of the body is maintained} but it is a balance which is in a state of continual oscillation. In no two successive moments is the chemical state of the body likely to be the same. Yet the contribution made to the body by the internal organs of secretion is most dependable with respect to the constancy of its chemical composition. Other factors which contribute to the chemical composition of the body are by far less reliable. One of the characteristics of living substance is its evanescent existence. A lump of sugar on the shelf will remain sugar indefinitely} the same lump of sugar, promoted to the rank of living substance in the active muscle, is rapidly broken up into relatively simple and stable compounds, which are eliminated from the body as waste. The living body wastes rapidly and must be continually repaired and replenished from the outside. The materials from the outside, taken into the body, cannot quite be depended on to maintain the latter in exactly the same chemical composition in successive times. True it is that the machinery of the body is such that, on the whole, it will absorb from the outside only those sub-

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stances which are conducive to the maintenance of its particular chemical composition. Examined from time to time, however, that composition exhibits marked differences. Consider the effect of differences in mere quantity of such a simple substance as water. Roughly speaking, the degree of intensity of the feeling of thirst is in proportion to the need of water by the body. But this proportion is far from being exact, and provisions exist in the body for storing superfluous amounts of this fluid and releasing it as it is needed. The body, as a whole, is thus more or less watery at different times; to be more exact, the solid substances of a number of tissues in the body exist in a more or less concentrated solution at different times. More concentrated solutions of salts have different electrolytic and other properties from less concentrated ones. T h e reactions of the body in different states of concentration must, for that reason, be different at different times. And now consider the effect on the body of the different food values of the variety of substances consumed—the caloric difference between a pound of sugar and a pound of lean beef; the difference in the vitamin content between a pound of starch, a pint of cream, and a pound of cabbage. Sugar and starch are fuel for the muscles and an insufficiency of these substances results in a reduction of their activity. But a diminution of the elusive vitamin content in food is followed by a variety of abnormal states, some of which are fatal. Moreover, as the digestive and absorptive functions vary from time to time, the "food value" of food taken ceases to be an absolute value and becomes relative to the particular state of the digestive organs at the time. W e have seen how the digestive process can be initiated, continued, retarded, or arrested as a result of certain sensory experiences—by certain sound waves impinging on the ear, by certain light rays impinging on the retina, by certain odors affecting the olfactory membrane of the nose. A state of anxiety, with the consequent retardation or arrest of digestion, may result in processes of fermentation of undigested or partly digested food in the gastrointestinal tract, with the production of toxic substances, which when absorbed into the blood may aggravate or maintain the unwholesome mental state. Not only is it true, therefore, that "what is food to one is poison to another," but it is likewise true that what is food at one time may be poison at another time. T r u e it is that the tissues of the body are provided with means for counteracting such internal difficulties and of rectifying their disturbed

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chemical balance; but while the body is engaged in overcoming such internal difficulties, its reactions to disturbances arriving from its surroundings must be modified in certain ways. T H E P E R M A N E N C E AND S P E C I F I C I T Y OF T H E B O D I L Y C H A N G E S

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ING FROM T E M P O R A R Y E M O T I O N A L DISTURBANCES

Under the pressure of a multitude of environmental situations, organisms have evolved the capacity for responding to each of a number of situations by appropriate reactions, each reaction being the expression of an internal change of a definite kind. " E v e r y response to a situation in the external environment," says Cannon ( 1 3 ) , "is associated with disturbance in the internal environment . . . every move in relation to the outer world must be attended by a rectifying process in the inner world of the organism." " T h e chief agency in this rectifying process, . . . is the sympathetic division of the autonomic system" ( 1 4 ) . In this connection, however, certain facts of surpassing importance must be borne in mind. One such fact is that an internal disturbance of the organism, upon subsiding, leaves a trace behind it in the form of a more or less permanent organic change. For although it is true that the organism, after the subsidence of a disturbance, springs back toward its original state, that state is never quite attained. Nor is it at all conceivable that the organism could by any possibility return to the exact point at which it was disturbed. Such a return would be possible only in the case of a body possessed of absolute elasticity, and such bodies do not exist. N o spring, after having been once wound, returns, upon unwinding, to its original form; no heavenly body describes the same orbit in successive times; no container holds the same amount of liquid twice. A l l bodies are more or less plastic, and the animal body is considerably so. It will be readily seen that if the organism were to return after each disturbance to quite its original state, so that no trace of the disturbance were left, then each such successive disturbance would of necessity be a totally new event to the organism, separated from all •preceding events by an impassable chasm and having no connection with them whatever. T h e phenomena of memory and of association, which consist of more or less permanent changes brought about by previous disturbances, directly contradict such an assumption. Another important fact to be borne in mind is that inasmuch as the responses of the organism are appropriate to each particular external situation,

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the internal disturbances which underlie the different specific responses must be correspondingly different and specific. Such a variety of internal disturbances underlying different modes of response we have seen made possible by different combinations of local activities of the autonomic system; by a variation in the respective quantities, and perhaps qualities, of the different internal secretions; by the different quantities of certain substances released for consumption from the tissues in which they are stored; and in other ways. The phenomena of memory and of association, which correspond to different external situations, are plainly indicative of the fact that the internal disturbances which have resulted in those more or less permanent changes, whether by different combinations and permutations of local activities or in other ways, are likewise different and specific. A third fact of great importance in this connection is the increasing and specific modification of behavior by accumulated memories of experiences— by the more or less permanent specific bodily changes resulting from the internal disturbances which underlie the responses to external situations. The increasing modifications of behavior bear the implication that the changes wrought in the organism by successive internal disturbances are of a cumulative nature. T h e possible mechanism by which behavior is modified by past experiences will be presently examined. SUMMARY

1. Only nerve impulses which enter the cerebral cortex may be productive of the subjective experience of a sensation, though not necessarily so even then. 2. The subjective experience of sensation implies a widespread internal disturbance which corresponds more or less accurately in certain ways to an external disturbance, and which, upon subsiding, leaves a relatively permanent trace of change indexed by the mental phenomenon of the memory of the event. It is by means of this relatively permanent record that separate experiences are interconnected. Since the bodily change which characterizes the subjective experience of sensation corresponds to the external disturbance which was productive of the sensation, the process is significant of that increasing adaptation of the organism to its surroundings which constitutes learning. The biological significance of the subjective experience of sensation is therefore an ability to bring past individual experiences to bear upon present activity.

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3. The thalamus is the last and largest relay station of nerve impulses on their way to the cerebral cortex. T h e hypothalamus contains nerve structures which are connected on the one hand with the thalamus, and on the other hand with the autonomic nerve system, for the most general control of the vital vegetative functions of the body. Nerve impulses on their way to the cerebral cortex, which reach the thalamus, may therefore, before reaching their ultimate destination, set going a widespread disturbance of the vital capacities of the body. 4. The vital organs of the body—the blood vessels, the glands, the iris of the eye, and all the internal organs—are innervated by the autonomic nervous system. The iris of the eye, the internal organs, and some of the blood vessels, are supplied by the two divisions of that system, either by the middle and the upper, or by the middle and the lower. The two divisions, which are antagonistic in their functions, are in every respect reciprocally cooperative. For example, while the upper autonomic contracts the pupil of the eye in a bright light, the middle autonomic, whose function is to dilate it, is inactive at the time; while the middle division dilates the pupil in a dim light, the upper division remains for the time being inactive. 5. Whatever small amount of control is exercised by the cerebral cortex over the autonomic nerve system, it is greater over the upper and lower (cranial and sacral) than over the mid-autonomic. For example, the sound and the sight of a person in the act of urination—stimuli which are effective only through the mediation of the cerebral cortex—are in the observer productive of the activity of the lower autonomic, whose function is to contract the urinary bladder. Other examples have been given in the text. 6. The cerebral cortex, however, exercises a large amount of control over the entire autonomic system in very indirect and roundabout ways. This is exemplified by the knowledge of the action of drugs which either enhance or counteract the activity of any of the divisions of the autonomic system. 7. The adrenal medulla secretes a substance, adrenin, whose action reinforces that of the mid-division of the autonomic system by which it is innervated, with the exception that it has no effect on the sweat glands. In addition, this substance reduces the fatigue of skeletal muscles and increases the coagulation of the blood. Reference is made in the text to the action of other humoral substances which modify the activity of different parts of the autonomic system. 8. Different bodily reactions are made possible by the activity of the autonomic system, through permutations and combinations of its local activities and by the different effects produced under different internal and ex-

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ternal conditions of the body. Every bodily reaction, therefore, has underlying it a characteristic activity of the autonomic nerve system. REFERENCES

1. Sherrington, C . S. T h e Integrative Action of the Nervous System. London, Constable and Co., Ltd., 1906. 2. Sherrington, C . S. " O n Reciprocal Innervation of Antagonistic Muscles. Third Note." Proc. Roy. Soc. of London, Series B, L X ( 1 8 9 7 ) , 414. 3. Darwin, Charles. T h e Expression of the Emotions in Man and Animals. 1873. 4. Hess, W . R. " T h e Autonomic Nervous System." The Lancet, I I ( 1 9 3 2 ) , 1199. 5. Gaskell, W . H. T h e Involuntary Nervous System. London and New York, Longmans, Green and Co., 1920, p. 1 4 1 . 6. Schübe, Purcell G., Max Ritvo, Abraham Myerson, and Ruth Lambert. "Human Autonomic Pharmacology. I V . T h e Effect of Benzedrine Sulfate on the Gallbladder." New England Jour, of Med., C C X V I ( 1 9 3 7 ) , 694. 7. Dameshek, William, Julius Loman, and Abraham Myerson. "Human Autonomic Pharmacology. V I I . T h e Effect on the Normal Cardiovascular System of Acetyl-Beta-Methylcholine Chloride, Atrophine, Prostigmin, Benzedrine—With Especial Reference to the Electrocardiogram." Amer. Journ. of the Med. Set., C X C V ( 1 9 3 8 ) , 88. 8. Myerson, Abraham. "Human Autonomic Pharmacology. X I I . Theories and Results of Autonomic Drug Administration." Journ. A. M. A., C X ( 1 9 3 8 ) , 101. 9. Lesses, Mark F., and Abraham Myerson. "Human Autonomic Pharmacology. X V I . Benzedrine Sulfate as an Aid in the Treatment of Obesity." New England Journ. of Med., C C X V I I I ( 1 9 3 8 ) , 119. 10. Myerson, Abraham, Julius Loman, and William Dameshek. "Physiologic Effects of Acetyl-Beta-Methylcholine (Mecholyl) and Its Relationship to Other Drugs Affecting the Autonomic Nervous System." Amer. Journ. of the Med. Sei., C X C I I I ( 1 9 3 7 ) , 198. 11. Brown, George E., and Alfred W . Adson. "Physiologic Effects of Thoracic and Lumbar Sympathetic Ganglionectomy or Trunk-Section." The Vegetative Nervous System, Assoc. Research Nerv, and Ment. Dis. (Baltimore, Williams and WilkinsCo.), I X (1930), 721. 12. Cannon, W . B., J. T . Lewis, and S. W . Britton. " T h e Dispensability of the Sympathetic Division of the Autonomic Nervous System." Boston Med. and Surg. Journ., C X C V I I ( 1 9 2 7 ) , 5 1 4 . 13. Cannon, Walter B. " T h e Sympathetic Division of the Autonomic System in Relation to Homeostasis." The Vegetative Nervous System, Assoc. Research Nerv, and Ment. Dis. (Baltimore, Williams and Wilkins C o . ) , I X ( 1 9 3 0 ) , 181. j 4. Cannon, Walter B. T h e Wisdom of the Body. N e w York, W . W . Norton and Co., 1932.

CHAPTER

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T H E EXPRESSION AND T H E EXPERIENCE OF T H E

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T H E C E R E B R U M FROM T H E P O I N T O F V I E W OF AN I N T E G R A L P A R T O F T H E BODY

W e have seen that one of the conditions by virtue of which a nerve impulse becomes a sensory impulse is its entry into the cerebral cortex. We must now examine the particular attributes of the cortex which enable it to bring about such a transformation. A point to be borne in mind is that every operation of the autonomic system in the body is productive of corresponding effects on the cerebral cortex. The larger blood vessels of the cerebral cortex are in all probability supplied with mid-autonomic innervation. The varying quantities of blood in the cerebrum are, however, largely determined by the state of the blood vessels in the body. When the latter are contracted, a larger supply of blood is pushed into the cerebral cortex, and a smaller supply of blood is determined to that organ when the blood vessels in the body are dilated. In the course of operations on the skull of epileptic persons, in whom a removable cause of the disorder had been suspected, it was noted that if the patient happened to have a seizure during the operation, the surface of the cerebrum at first became blanched, then congested, cyanosed and bulging ( i ) . The engorgement of the cerebral blood vessels is in all probability due in such cases to the intense rigidity of the muscles, the result of which is to squeeze out from their blood vessels a quantity of blood. That the blood vessels of the cerebrum are subject to the same diseases as those of the rest of the body is a fact with which every physician is familiar. The hardening of the cerebral arteries, like those of the rest of the body, is a common enough calamity. Vascular naevi, the same as those which occur on the skin, are known to affect the surface of the cerebrum. Everybody has experienced the mental dullness, the defect of memory, and other disagreeable manifestations of the retardation or perversion of

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cerebral activity on hot and humid days, or on very cold days, or after an indigestible meal, or as a result of any one of a number of other unfavorable conditions to which the body is subject. In brief, though the cerebrum is a highly specialized organ, one must not lose sight of the fact that, being an integral part of the body, it is influenced by every agency, internal and external, which affects the mechanical, physical, and chemical balance of the body from moment to moment. T H E F U N C T I O N S OF T H E T H A L A M I C P L E X U S

The nerves which extend from the receptor organs on the surface of the body, from the muscles and joints, and to a less extent from the viscera, enter the central nervous system and establish connections directly, or by means of interposed nerves, with two sets of motor nerve cells. The nerve fibers which extend from one such set of cells—the ventral—leave the central nervous system and pass without interruption to innervate the skeletal muscles. The nerve fibers of the other set of cells—the lateral—upon leaving the central nervous system enter the autonomic nerve ganglia. The cells of the latter send out, in their turn, nerve fibers for the innervation of the glands, of the smooth musculature of the internal organs, of the blood vessels, and of the hair muscles. A disturbance imparted to a receptor organ is therefore capable of propagating a nerve impulse which will bring about a contraction of the skeletal muscles and at the same time activate the vital machinery of the body for the production and transportation of the substances which furnish these muscles with motive power. Since the particular form of the nervous system was evolved under the impacts of external forces, the organization of its cells and fibers is such that a given disturbance of the receptors is productive of an activity of the vital machinery and of the skeletal muscles which corresponds in a more or less definite way to the particular kind of disturbance. Such is the significance of any reaction of the body. At successively lower levels of the central nervous system, the nerve mechanisms for muscular movements, coordinated into responses to external situations, become increasingly simple and fixed in character. A given stimulus applied to a receptor organ at successive times brings about a relatively uniform response by movement. A familiar example of such fixed mechanism is one contained in the lower part of the spinal cord. When this nerve mechanism is activated by striking the patellar tendon, the almost invariable result is a movement of extension of the leg at the knee. Another,

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less familiar example is Graham Brown's (2) observation that immediately upon severing the spinal cord of an animal, its legs execute a number of the coordinated movements employed in the act of running. The statements made in the last paragraph must be somewhat qualified. They are sufficiently accurate as applied to the higher vertebrates—those in possession of a relatively large cerebrum. As we descend in the vertebrate scale to animals like the frog and the lizard, with a rudimentary cerebrum, we find the lower portions of the central nervous system capable of considerable modification of reactions. On the whole, it appears that as we ascend in the vertebrate scale, the cerebrum exercises an increasing degree of monopoly of nerve functions, relegating to the nerve structures below it the relatively simple and fixed functions of coordinating the activity of a number of muscles into fixed patterns of movement. We have seen, however, that even the simplest response by movement necessitates for its execution the mechanical, chemical, and physical activities of a number of organs. With the rise in the animal scale, the body becomes capable of responding to increasingly complex external situations, and the nervous organization of the vital machinery, whose activity underlies these responses, becomes likewise of increasing complexity. Hence the intricate mechanism of the thalamic plexus for the coordination of the vital activities with the functions of the cerebral cortex. Clinical observation is to the eifect that within the thalamus and the hypothalamus is resident the highest, that is, the most general, control of the vital autonomic functions. Disease or injury of certain of these parts is known to result in profound disturbances of such functions as the maintenance of the average water-constant in the body, of a constant temperature, of the processes of growth and repair of tissue, of the normal periods of sleeping and waking—functions of so fundamental and general a character that their disorder must pull every special function of the body out of its normal course. An adequate nerve impulse proceeding from the receptors, which succeeds in reaching the structures of the thalamus, is therefore potent to evoke any or all of the activities of which the autonomic system is capable—potent to call forth the most widespread emotion of the vital machinery of the body, together with the expression of such an emotion by the movement of the skeletal musculature and in other ways. We must glance at the facts. When the thalamus has been injured in human beings by a tumor, a hemorrhage, or other abnormal condition, the subjective experience of the

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sensations becomes abnormal in a number of ways. Instead of being correctly localized and graded in kind and degree, the subjective experiences become ill-defined, poorly localized, and abnormally intense. It will be remembered that not only does the thalamus contain the highest centers of the autonomic nervous system, capable of setting in motion any or all of the activities of the vital machinery of the body, but that it is the last and largest relay station of the sensory nerves on their way to the cerebral cortex. With the solitary exception of olfactory impulses [says Clark ( 3 ) ] , all sensory impulses which are destined to reach the cerebral cortex have first to be filtered through the mass of grey matter which is found in the wall of the third ventricle, the optic thalamus. . . . It is possible for sensory impulses on their way through the thalamus to undergo modification and selection as the result of being brought into relation with the activities of intrinsic thalamic mechanism. . . . Long before the neopallium has appeared in evolutionary history, a mechanism is provided for the interaction and blending of these diverse afferent impulses, and, in relation to this plain anatomical fact, it may be noted that there is accumulating evidence based on clinical and psychopathological observation that the thalamus is the anatomical equivalent of the very threshold of consciousness. W e must examine the part which the function of the thalamus plays in the conscious state. T h e work of Roussy ( 4 ) , of H e a d and Holmes ( 5 ) , and of a large number of other investigators has thrown a flood of light on this formerly very obscure subject. Under normal conditions an external disturbance must reach a certain degree of intensity to be productive of the experience of sensation; but once a sensation is experienced, it is subjectively localized in the exact place on the body affected, and it is recognized as having been caused by a particular class of external agency of a given strength. T h u s when an object is in contact with the body, the person can distinguish the object as being either rough or smooth, cool or warm, blunt or pointed; and he is aware of the exact spot on the body which has been touched or pressed or pricked or scratched. A very important point to bear in mind in this connection is that the responses of a normal person, by movement and by emotion, to any disturbance affecting his receptor organs may take place immediately or they may be postponed, and that they may be out of all proportion to the magnitude of the disturbance. It may be a blow for a blow, a smile for a blow, a blow for a smile, or a hundred blows by way of response to a dis-

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turbance imparted to the auditory receptors by the slight force of a spoken word. Such is not the case when the thalamus has been injured in a way to sever a number of the nerve connections between it and the cerebral cortex. Under these conditions an external disturbance must, in the first place, be of greater magnitude than under normal conditions in order to be productive of any subjective sensory experience; in physiological language, the threshold of stimulation is higher than normal. In the second place, the person cannot localize exactly the spot on his body touched or pricked or scratched} instead, he localizes the contact as being anywhere within wide limits. In the third place, his subjective experience regarding the kind of contact is very faulty. H e may not be able to distinguish between a warm and a cool object, between the contact of the head of a pin and its point, between a rough and a smooth surface. Poorly localized and g r a d e d — i l l defined—as the subjective experiences may be in such cases, they are, however, very much intensified. A n y disturbance of the receptor organs, once it is adequate to be subjectively experienced, becomes either an intensely agreeable or an intensely disagreeable experience, and the reaction — t h e response—to such stimulation is immediate and intense. I have seen this in a number of instances. Passing the blunt point of a lead pencil over the skin of such a person's abdomen, for the purpose of testing the abdominal reflexes, frequently called forth loud cries of suffering and writhing, almost convulsive movements of the entire body. T h e studies made by H e a d and Holmes ( 5 ) of such patients furnish detailed information on this subject. Those interested will find instruction in reading these authors' records of such patients. Some of these patients have been studied by them for a number of years. On the whole one sees throughout their histories a heightened threshold of stimulation, a defect in localization and discrimination, a perverted or exaggerated subjective experience of an emotional kind, and an immediate and intense response. A few partial quotations from the histories of two such patients by the last-named authors must suffice to elucidate the subject in hand. It will be noted from these histories that the abnormal subjective experiences are referred by these patients either to one side or the other of the body} and this corresponds to the opposite injured side of the thalamus. Case 8. A man aged 64: An instance of the thalamic syndrome where cutaneous sensibility was not diminished. All fleasant or disagreeable stimuli, more farticularly heat and cold, ;produced a frofoundly greater response on the affected half of the body. . . .

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Spontaneous sensations.—He complains of a constant "soreness" of his left hand and his left foot, and of similar pain in the left half of his tongue. The whole of the left side also "feels cold," and anything that touches it seems unpleasantly cold to him. H e always wears a glove on this hand. T h e whole of this side is also tender j when he places his foot on the ground, for instance, "it feels as if there were tintacks under the foot." H e also complains of "a painful tingling" throughout this side, of a "gnawing pain" in the left temple, and occasionally "sharp pains" shoot through the left limbs. . . . Tickling and scrafing.—The left side of the body is . . . more "tender" to scraping than the right. . . . Sensibility to fain.—The left limbs and the whole of the left half of the body, including this side of the face and tongue, are "more sensitive" to pricks than similar parts of the right side, and the reaction thereto and the emotional expression are considerably greater. When a pin is drawn across his chest from the right to the left side he immediately complains that it is more painful to the left of the middle line. . . . Pressure-fain.—The algometer produces intolerable pain on the left side, and a sudden and violent reaction. As soon as pain is evoked he writhes and jumps j moreover, its effects persist longer than on the right side. . . . Thermal sensibility.—. . . Any temperature that is definitely cold to the left side causes an expression of discomfort and an excessive reaction j a tube a few degrees below the threshold is "just cold" to the right hand, but "very cold, very unpleasant" to the left. Similarly, even 45° C., which was described as warm on the right hand, was "too hot and uncomfortable" on the left. When, however, milder degrees of warmth, as 38° C., are employed, or if the hands are placed on a vessel containing water at this temperature, he describes the sensation evoked in the affected hand as "delightful," or "more soothing and more pleasant than on the right." Further, he states that this gives him not merely local pleasure, but "makes him feel happy all over," and this is clearly indicated by his general reaction and expression. Case 12. A man aged 65: An instance of the thalamic syndrome where all loud sounds froduced great distress and much increased the involuntary movements on the affected side. . . . Sfecial senses.—Smell, taste and vision are unaffected. On the other hand, hearing shows the following changes: If a tuning fork is held near either ear, whilst he is in an absolutely quiet room, he listens for a few seconds calmly and then becomes more and more agitated; his face shows obvious signs of discomfort and the involuntary movements of the affected arm become greatly increased, or they may be started by the sound of the fork. . . . Our impression after several examinations is that it is easier to produce these effects from the left ear. Moreover, he is certain that he dislikes the fork more when it is approached to the left

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ear than to the right. Music, of which he used to be unusually fond, is now intensely disagreeable j even favorite tunes "now work me up till I can't bear them," and excite the involuntary movements to great violence and amplitude. On the day he traveled to London the noise of the railway was so intolerable to him that he attempted to throw himself out of the train. No musical sounds are now capable of giving him pleasure. . . . Spontaneous sensations.—He complains of constant pains over the whole of the left half of the body, sometimes stationary in the neighborhood of the great joints, sometimes shooting through a limb or over the whole side. They are liable to be evoked by peripheral stimuli that cause discomfort. H e also complains of a "numbness" down the left half of the body, "as if it had been hurt and bandaged up." The left side and this half of the face seem to him to be puffed and swollen, and there is a "cold feeling" round the left eye. If he lies on the left side it seems as if he were "on a hard lump." Tactile sensibility.—There is complete loss of sensibility to contacts with cotton wool on the left arm, left leg and this half of the trunk, but he occasionally responds to wool rubbed over the left ear and forehead. Pressure-touch is also gravely diminished. Roughness.—He appreciates roughness, as tested with Graham-Brown's instrument, within normal limits on the right half of the body, but even when the protrusion is five times this amount he fails to recognize the scraping of the instrument on the left side. Under these conditions he merely says, "Something is happening to me, but I don't know if you are doing anything." Tickling and scra-ping.—Although cotton wool may not be appreciated over the left lower limb, a wisp repeatedly rubbed over the sole produces a sensation of painful "tingling all up the leg." When the pulps of the fingers are gently drawn over the right sole he smiles but remains still, but when the same stimulus is applied to the left sole his face shows obvious discomfort and he says, "You are tickling me, but it does not seem any place in particular j it is a crawling feeling which affects me all up the side." When the left sole is scraped with the finger-nails he shows signs of distress and says, "I don't know what you are doing, but it affects me all up the side." Both tickling and scraping excite and exaggerate the involuntary movements. Vibration.—The appreciation of vibration is totally lost on the left limbs and on the left half of the trunk, and no unpleasant sensations are provoked by the application of the strongly vibrating fork. Sensibility to pain.—He generally fails to appreciate moderate single pricks on the left upper limb, but when pricked more firmly, or several times in succession, he reacts vigorously, describes the sensation as "something burning," or "a sharp, fiery prick," and says it is much more painful than on the opposite side... .

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Pressure-fain.—The pressure necessary to evoke pain is uniformly higher over the left than on the normal half of the body, but the pain evoked is excessive.... Thermal sensibility.—All appreciation of temperature is abolished on the left half of the body. Ice produces an uncomfortable sensation over the affected parts, which he describes "as if something pricked me and made me jump," and the reaction is greater than from the normal side. No temperature between io° C. and 50° C. produces any reaction. Sense of position and of passive movement.—He is totally unable to recognize the posture or passive movements of the left limbs, and makes no attempt to say in what direction they are moved. Localization.—He has lost the power of recognizing the locality of all stimuli, including prick and painful pressure. H e can generally recognize in which limb pain is evoked, but has no idea what part of the limb the stimulus affects. Appreciation of weight.—He is unable to appreciate weight in the left hand and cannot even recognize the difference between 30 and 700 grm., whether the hand is supported or not. T h e power of appreciating form is also abolished in the left hand. So extensive is the human cerebral cortex that diseases involving small areas do not cause any appreciable increase in the manifestations of the thalamic functions. W e have seen, however, that when large portions of the cerebral cortex are experimentally removed or are affected by disease, or are congenitally absent, the free play of the thalamic functions becomes manifest in the ease with which emotions and their accompanying expressions are set going. It is therefore reasonable to conclude that the low degree of sensory discrimination, the intensity of the emotional experience and the exaggerated and immediate response, which constitute the symptom-complex of injury of the thalamus, are due to the severance of the nerves which connect it with the cerebral cortex. W e must therefore assume that under normal conditions the cerebral cortex exerts a controlling influence over the functions of the thalamus. T h e kind, extent, and the possible nature of this controlling influence must next be elucidated. T H E E F F E C T OF N E R V E IMPULSES A R R I V I N G FROM T H E C E R E B R A L CORTEX AT T H E T H A L A M U S

W e have seen that nerve impulses resulting from a disturbance of the receptor organs, upon reaching the thalamus may be productive of changes of a certain magnitude and kind throughout the body. If these nerve impulses next succeed in emerging from the thalamus and (by way of the thalamocortical nerves) in entering the cerebral cortex, they are there changed in

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such a way that upon returning to the thalamus again (by way of the corticothalamic nerves) (fig. i g ) , the bodily disturbance previously set going may be either enhanced or diminished, or changed in kind, or entirely discontinued. L e t us glance at the possible causes of such a changed effect on the thalamus by the nerve impulses after their passage through the cerebral cortex. 1 . Mention was made in a preceding section that the capacity of nerves for the conduction of nerve impulses varies with their condition at the time. Laboratory experiments and clinical observations have shown that minute differences in the chemical composition of the substances surrounding a nerve, slight differences in temperature, and a number of other causes make for great differences in its activity (6). T h e vast number of nerves which make up the bulk of the cerebrum, bathed as they are in the tissue fluids of the body, are therefore subject to pronounced variation in their activity with slight changes in the composition of the body fluids j and we have already seen that the composition of the body fluids, although roughly constant in the long run, varies from time to time, owing to a number of internal and external causes. The variation in the burning of a combustible string in a dry or a damp atmosphere, containing more or less oxygen, is a distant analogy. 2. T h e nerve pathway is made up of a number of nerves placed end to end, and the nerve impulses, as they proceed along that pathway, are relayed from nerve to nerve. Laboratory experiments have shown that these relay stations, or as they are known to physiologists, synapses, are points at which nerve impulses are subject to great modification ( 7 , p. 1 8 ) . These points are apparently most affected by the changes in the chemical and physical condition of the body fluids, and the nerve impulses, in crossing those points from the end of one nerve to the beginning of another, are correspondingly affected. At such points the recovery from the change implied by the passage of a nerve impulse may be retarded, and the nerve impulses entering such an incapacitated region are apt to be extinguished. Again, the passage of nerve impulses across this vulnerable point may be merely retarded, but, once the point is passed, they may proceed along the next stretch of the nerve pathway at a normal rate in the same manner that a flame, moving from point to point along a combustible string, may be slowed down at the point at which the string is moistened, but once it has struggled through that point, will proceed along the rest of the string at a normal rate of progress.

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3. In the central nervous system most nerves begin and end in a number of branches, and the arrangement is such that in some instances the endings of one nerve come in contact with the beginnings of a number of nerves, while in other instances the endings of a number of nerves make contact with the beginnings of a single nerve (fig. 2). A relay station for nerve impulses is therefore a point at which a number of nerves converge on one nerve and at which the branches of each nerve diverge and come in contact with a number of nerves. W e have already seen that such a divergence of the branches of one nerve and the convergence of a number of nerves on one nerve make for a difference in the number, the rate of propagation, and the timing of successive impulses. A n increase in the number of points at which the nerve impulses are relayed from one nerve to another, in the course of the nerve pathway, must therefore make for an increasing degree of modification of effects. T h e most obvious characteristic of the cerebral cortex, especially of the human cerebral cortex is, as we shall presently see, the large number of nerves, and consequently the large number of synapses, which make up its nerve pathways. T h e number of nerve fibers which enter the thalamus from below on the way to the cerebral cortex is relatively small, probably not more than 1,000,000. Within the thalamus, however, the branching of the fibers which enter it, and the branching of the thalamic cells to which the impulses are relayed, result in a much larger number of nerve fibers proceeding from it to the cerebral cortex. For a number of anatomical reasons this number is difficult to estimate, but it is probably in the neighborhood of 10,000,000. T h e nerve impulses traversing these nerve fibers are, upon their entry into the cerebral cortex, communicated to a number of nerves so vast that the error involved in its approximation must be of the order of hundreds if not thousands of millions. M y own estimate of this number is in the neighborhood of 12,000,000,000. This number agrees closely ( ! ) with such cell counts previously made by other investigators (8). 1 Far from exact as such cell counts are, they furnish a general conception of the number. 1 T h e differences in the size and the richness in the convolutional pattern of different human cerebrums is very considerable. A richer convolutional pattern makes, of course, for an increase in the surface area. T h e average surface area of the cortex of the specimens measured by me was in the neighborhood of 120,000 square millimeters, while Economo's (8) estimate is 220,000. Again, my estimate of the average thickness of the cerebral cortex is about 3 millimeters, while Economo gives it at 2.5 millimeters. Economo estimates the number of cells at about 14,000,000,000. It is possible, of course, that the thickness of the cortex makes up for its extent, but the probability is that the estimate of one or of both investigators is erroneous.

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T h e effect of a nerve impulse communicated to this vast aggregate of nerves may be likened to a spark communicated to a magazine of explosives. True it is, as we shall see later (Chapter X I , " T h e Epileptic Seizure"), that the particular magazine we are considering is provided with appliances for extinguishing the flames set going at any point in their course. When not extinguished, however, the multiplication of effects in the cerebral cortex can be to some extent conceived. The nerve impulses which traverse the pathways of the cerebral cortex converge upon the emerging—efferent—nerve pathways. The number of nerve fibers which the latter contain is relatively small, being probably of the same order as that of the entering fibers. Each of the special classes of receptors—of light, of sound, of muscle-sense, of touch, and the others— is represented in a separate small area of the cerebral cortex. The large extent of the cerebral cortex is due not to the combined areas for the reception of the sensory pathways, but to the pathways connecting the several receptive areas. For the reason that these latter pathways establish connections between different points in the cerebral cortex, they are anatomically known as intercortical pathways (9). There is an immense amount of clinical, pathological, psychological, and physiological evidence, some of which will be examined in the later discussions of the subject, pointing to the fact that these intercortical pathways are the repositories of memories of past experiences} or, to express the same thing in a more scientific way, that these nerve pathways are more or less permanently changed in certain ways by the passage along them of nerve impulses from the end stations in the cortex in which the several receptor organs are represented. W e shall see later (Chapter V I I , " T h e Effect of Injuries of the Association Systems") that the effect of an injury to the areas of the cortex occupied by the intercortical systems of nerves is in many ways different from one to the end stations— the primary receptive areas—of the cortex (Chapter X , "Hallucinations in Certain Injuries and Diseases of the Nervous System"). Suffice it to note in this place that an injury to the cortical area in which terminate the pathways which transmit the impulses of light, is productive of blindness; an injury to the cortical receptive area of the nerves transmitting impulses of sound, is productive of deafness, and so forth; but an injury to the cortical areas containing the nerves which interconnect the sensory receptive areas is not productive of anesthesia in any sphere of sensation, but results instead in a loss or distortion of parts of the memories of all objects and conditions, to an extent which is directly proportionate to the extent of the injury. It

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will, however, appear that in different cortical areas these intercortical systems differ in the degree to which the memories of attributes of objects and conditions are integrated. Owing to the fact that the intercortical nerve systems are the repositories of organized memories of different attributes of objects and conditions—the repositories of associated memories—they are known as association systems. We may now attempt to trace in a very general way the course of nerve impulses set going by a disturbance imparted to a receptor organ—to a touch corpuscle in the skin, a taste bud on the tongue, the retina of the eye, the cochlea of the ear, or any other. The fact has already been noted that nerves, upon entering the central nervous system, divide into a number of branches j that the greater number of these branches, before proceeding very far, establish connections with two sets of motor cells in the spinal cord and the brain stem, one set for the skeletal muscles, the other for the autonomic system} and that a smaller number of such branches, on their way to the cerebral cortex, are relayed in the thalamus (fig. i c ) . Nerve impulses which succeed in reaching the two sets of motor cells by way of the relatively short nerve branches, may initiate contractions of the skeletal musculature and a corresponding amount of activity of the vital machinery, with the production of certain movements and postures. If impulses proceeding toward the cerebral cortex succeed in reaching the relay of the thalamus, they are productive of more intense and more widespread changes in the body—blood vessels may contract here and dilate there; certain glands may begin, others cease to secrete ; the heart beat may be accelerated or slowed and become either stronger or weaker; the respiratory movements may become more frequent or less, and either deeper or shallower; and so forth. These activities, in their turn, either initiate or inhibit other vital activities. In brief, the nerve impulses in question, upon reaching the thalamus, may result in a great agitation or emotion of the vital capacities of the organism, releasing a certain amount of stored up energy and leaving in its wake more or less permanent changes. Those who are inclined to doubt that certain changes of a more or less permanent nature take place in the body as a result of nerve impulses potent to set going an emotion of the vital capacities, need only to be reminded that if a muscle, as a result of much exercise, becomes visibly larger in volume and harder to the touch, then it must be true that as a result of less exercise, that muscle must have become somewhat larger in size and of somewhat harder consistency than it had been before the exercise, though

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not visibly and palpably so. If stepping a million times on solid marble results in a visible impression of the human foot, then stepping once on the marble must leave an impression one-millionth part as deep. The fact that any machine is finally worn out as a result of doing a certain amount of work signifies that it was permanently changed in a certain way with each step in the progress of the work. If the nerve impulses in question, after their passage through the thalamus, next reach the cerebral cortex, and after passing through its countless association systems are then returned to the thalamus again, the emotion previously set going may be either augmented, reduced, changed in form, or discontinued. The fact is that nerve impulses, in their passage along the association systems of the cerebral cortex, are modified in a certain way. Let us examine this fact more closely. Outside of the pathway which returns nerve impulses from the cerebral cortex to the thalamus, three other emerging pathways are known. Two of these do not interest us in connection with the subject immediately before us. The third, consisting of very long nerve fibers, descends to several levels in the brain stem and the spinal cord and there establishes connections with the motor cells for the innervation of the skeletal muscles (fig. IF). The nervous mechanisms of the skeletal muscles, as well as the thalamic mechanisms for the emotion of the vital capacities of the body, are thus influenced by two sets of nerve impulses j one, arriving more or less directly from the receptor organs, the other, after its passage through the association systems of the cerebral cortex. The effect of the first set of nerve impulses, that which passes by the relatively direct and short route, is more or less fixed—a given disturbance of the receptor organs, causing a given combination of muscular contractions and an emotion of the vital capacities sufficient to furnish the muscles with the materials needed for their work. The effect of the other impulse—that which passes by the long way of the association systems—is not fixed but varied, this variation depending upon the particular kind and degree of modification to which it had been subjected in its passage through the cerebral cortex. A G E N E R A L F O R M U L A FOR T H E K I N D OF M O D I F I C A T I O N U N D E R G O N E BY N E R V E I M P U L S E S IN T H E I R PASSAGE T H R O U G H T H E CEREBRAL CORTEX

A general idea of the modification which nerve impulses undergo in their passage through the maze of the cerebral cortex may be gained by the following rather distant analogy.

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If a strip of steel is tapped at one end, a wave of vibration is transmitted along it to the opposite end. An object in contact with the far end of the strip will be affected by the vibrations in a certain way. And as long as the strip of metal remains in every respect the same, repeated tapping at one end of it must affect the object in contact with its opposite end in the same way. Actually, however, the strip of metal does not remain the same. Resistant as steel is, it actually changes in certain ways as a result of being traversed by gross vibrations. It becomes increasingly crystalline and harder, in consequence of which the shape, rate, and length of the waves of vibration are changed. The effect on the object in contact with its distal end is therefore different with each succeeding tap. The general formula expressive of the kind of modification successively undergone by the wave of vibration in the strip of steel is as follows: The successive waves of vibration are modified in correspondence with the modification of the strip of metal by preceding vibrations. And the following, too, may be reasonably taken to be the general formula for the change undergone by successive nerve impulses traversing the tortuous association systems of the cerebrum: Successive nerve impulses are modified in correspondence with the modification of the nerve pathways of the cerebral cortex by the passage of preceding nerve impulses. In the foregoing formula the discerning student may discover much significance. For, as has been stated above, the person's experiences are impressed in these nerve systems in a certain way. Whatever may be the particular nature of this impression, it is a change which constitutes a more or less permanent record of the impulses passing along these nerves. Any succeeding nerve impulses must, therefore, during their passage, be changed in a manner which corresponds to the changed nerve. More precisely, succeeding nerve impulses are, in their passage through the association systemsy modified in correspondence with the persons previous experiences. The effect which such a nerve impulse, after emerging from the cerebral cortex, must produce on the thalamic and the motor apparatus would therefore likewise be in correspondence with the person's past experience. It may well be asked why the nerve impulses which traverse the shorter nerve routes are not likewise modified, resulting in a behavior modified in accordance with previous experiences. To which the following answer may be returned: In the absence of a knowledge of the structural modifications in nerves, brought about by nerve impulses passing through them, we may, for the

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sake of the argument, take it for granted that the pathways of the lower portions of the central nervous system are as liable to be changed by nerve impulses passing through them as are the association systems of the cerebral cortex. As stated above, however, the effect of the nerve impulses is vastly amplified in the cerebral cortex by the great number of its contained nerves. The ultimate result of such an amplification must therefore be correspondingly pronounced. A survey of the animal world from that point of view corroborates the foregoing statement. The smaller the number of nerves in the cerebral cortex of any animal, the more direct and the less varied are its responses to disturbances imparted to its receptor organs. And when we come down to such an animal as the social wasp, whose brain is of the size of a small pinhead, we find a behavior characterized by an extremely small degree of variation and an extremely high degree of uniformity, and whose adaptations are therefore circumscribed within relatively narrow limits. Not so with man, who is able to vary his reactions in adaptation to a vast variety of conditions, who can live in almost every climate, on a great variety of foodstuffs, and who can mate in every season of the year. True it is that deprived of the tangible embodiments of the activity of his large cerebrum —of his written records, his teachers, and his tools—he would lose his knowledge and revert to a state of savagery in a single generation} but under favorable circumstances he could again acquire it by his capacity for modifying his behavior in accordance with the previous experiences which he is able to accumulate in his cerebrum—by his capacity for learning, while the animal whose brain is the size of a pinhead forgets little but can learn less. As a matter of fact, the acquisition of a vegetative habit, which appears to be at first sight in the nature of memory resident in the autonomic nerve system, is really a function of the cerebral cortex, which controls the autonomic system in indirect and, in some instances, very roundabout ways. The habits acquired regarding the time and the place for such vegetative activities as feeding, urination, defecation, sexual intercourse, and others of the kind, are lost or distorted with the loss or injury of the cerebral cortex. That control over the vegetative activities which is part of the social amenities, is lost with the degenerations of the cortex which characterize certain forms of senility, dementia, and other abnormal conditions. And this is likewise true of the loss of the acquired control over such emotions as rage, fear, grief, and love, under conditions which depress the

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functions of the cerebral cortex, such as alcoholic intoxication, an indigestible meal, or a disappointment. 2 T h e roundabout ways alluded to by which the cerebral cortex is able to control the functions of the autonomic system, are exemplified, as already mentioned, by the knowledge of the effect of drugs. T h e administration of atropine, which counteracts the influence of the cranial autonomic on the digestive apparatus, and of digitalis, which counteracts the influence of the mid-autonomic on the heart, are illustrative of the devious means by which the cerebral cortex subordinates the activities of the autonomic system. AN

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T h e following experiment is illustrative of the different effects produced on the motor and the thalamic apparatus by the two different nerve impulses — t h e one proceeding by the shorter and more direct route, the other, by way of the long and tortuous route of the cerebral association systems ( i o ) . Picrotoxin is a powerful poison which, in suitable doses, acts on a cat by paralyzing the functions of the cerebral cortex. Administered hypodermically, the effect of the poison is manifested in fifteen to twenty minutes. During that interval, the animal behaves in quite a normal way. An account of one such case follows. Immediately after the injection of a dose of picrotoxin, the cat rested quietly in the cage, facing the observer. T h e latter then suddenly clapped his hands together, producing the familiar loud sound. Thereupon the cat was startled, pricked up its ears for a moment, and glanced at the observer with an expression of surprise. W h e n the observer again clapped his hands a few seconds later, the cat, without being startled, again pricked up its ears for a moment, but less strongly than the first time and, glancing at the observer somewhat more intently, blinked its eyes and parted its lips for a second in the manner of the normal cat's grimace expressive of slight annoyance. W h e n the hands were again clapped a few seconds later, there was, in response, a hardly noticeable pricking up of the ears, followed by a brief glance at the observer, expressive neither of surprise nor of annoyance. A further repetition of the sounds brought forth no response, either by movement or emotion. T h e animal subsided to rest and simply paid no attention. 2 T h e social amenity w h i c h consists in being able to lie without blushing persists, however, even under the most depressing conditions.

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When, however, three or four minutes later the observer again clapped his hands, the cat was again startled, again pricked up its ears, and again exhibited surprise, the same as at first. A repetition of the sounds at intervals of a few seconds brought forth diminishing responses, the fourth arousing no response. The experiment was then varied by tickling the cat in the neighborhood of the ear with a straw. It responded by a momentary startle and, rising quickly to its feet, vigorously shook its head and made a movement as if about to walk off, but, evidently reluctant to make the effort, it subsided in a resting posture and half-closed its eyes. When, soon after, the offending straw again touched its ear, this time on the inside, the cat arose, vigorously shook its head, meowed, grimaced, turned about and, walking to the farthest wall of the cage, subsided with its back to the observer. Such is the behavior of the normal cat. Before showing the change in the animal's reactions after the functions of its cerebral cortex had been extinguished, it will be conducive to a better understanding if its normal behavior is first interpreted in physiological and anatomical terms. When a person receives an unexpected friendly slap on the shoulder from behind, he is startled. We shall later see that this startling reaction to unexpected—unappraised—disturbances, can be analyzed as a series of events which is of the order of the epileptic seizure. Essentially, the biological significance of the stiffening of the entire skeletal musculature in the startling reaction appears to be a fixation of the joints in preparation for any movement for which the emergency, when appraised, might call. Upon turning about and seeing the familiar face of the friend, the muscular reaction and the emotion of the vital capacities, together with the expression of anxiety characteristic of the startling reaction, disappear. Should the friend, now in full view, slap the person's shoulder once more, the latter will not be startled. And the same may be reasonably assumed to have been true of our cat. The disturbance imparted to the receptors of sound had set going impulses along the nerves which extend from the receptors to the central nervous system. The impulses proceeding along the shorter branches reached the motor and the thalamic mechanisms, with the result that the nerve mechanisms for muscular coordination, as well as the emotional capacities of the animal for sustaining the metabolic processes of the contracting muscles, were thrown into action. From the thalamus the nerve impulses then proceeded to the cerebral cortex and, very much amplified by spreading to the

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countless numbers of association pathways, converged in a shower of impulses on the relatively small number of emerging nerves. Not merely was the total number of impulses augmented in a quantitative sense, however. T h e effect of the incidence of the nerve impulses emerging from the cerebral cortex upon the thalamic and the motor mechanisms must be considered as qualitatively different from the nerve impulses which initiated the activities of those organs in the first place. For during the passage of the impulses along the pathways of the cerebral cortex, they were modified in correspondence with the modification of those pathways by preceding nerve impulses, that is, by the preceding experiences of the animal. T h e animal's response to the present situation was therefore modified in correspondence to its past experiences with similar situations. Its past experience, however, was to the effect that the sound of a friendly handclap, even though it be temporarily annoying, is in the long run harmless and not worth the effort of avoiding. T h e activity of the thalamic and of the motor mechanisms set going by the initial relatively direct nerve impulse which arrived from the receptors, was accordingly inhibited by the one whose effect is in correspondence with previous experience. One of the ways by which a nerve impulse may be inhibited by the arrival of another impulse we have already seen. The succeeding two repetitions of the handclap, at intervals of a few seconds, therefore, brought forth diminishing responses from the animal. And we may legitimately assume that the progressive diminution of the response was due to the still-continued shower of nerve impulses from the cerebrum; and that to this continued shower of cortical nerve impulses was due, as well, the failure of any response to the fourth repetition of the disturbance, after a short interval. After the lapse of some minutes, however, that shower of cortical impulses ceased and the impulses from the auditory receptors, set going by a renewed sound of the handclap, had the same effect as at the beginning of the experiment, succeeding handclaps at short intervals being marked by the same diminution of the response and by its ultimate disappearance. But the annoyance of the obtrusive straw was too great to risk a repetition of the event, this, in the cat's experience, being as apt to recur as the repetition of the less annoying and more harmless sound of the handclap. In conformity with its previous experience, therefore, the animal evaded the possibility of such a recurrence by walking away from the observer as far as it could. Such an interpretation of the animal's behavior, in terms of an extinction,

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by nerve impulses modified in their passage through the pathways of the cerebral cortex, of the unmodified nerve impulses arriving from the receptors, is corroborated by the changed behavior of the animal after its cerebral cortex was paralyzed by the action of a poison. T h e first noticeable symptom of the effect of the poison was an emotion of its vital capacities. This activity of the autonomic system was manifested by a flow of viscose saliva and by the dilation of its pupils. T h e sound of a handclap then resulted in a stronger response than before, and its repetition at intervals of a few seconds was not marked by any abatement of the reaction for seven successive times. A few minutes later the symptoms of poisoning became more pronounced. The animal reacted to the sound, no matter how many times it was repeated, and the successive reactions, instead of becoming weaker, became increasingly stronger. T h e increasing emotion of its internal machinery was manifested by its expression of intense fear, widely dilated pupils, wide-open eyes, a lashing of its tail from side to side, the bristling of its hair, and the arching of its back. It salivated profusely and defecated in a way which was unnatural to the normally tidy animal. In another three or four minutes the animal's behavior was such as to leave no doubt in the observer's mind that notwithstanding its exaggerated reactions to any disturbance, it was anesthetic and thoroughly disoriented. Although its eyes were wide open, it appeared not to see either the observer or the limits of its cage. The ordinary caressing call of the experimenter, to which the normal cat responded by the familiar movements of approach, had no effect upon it now. It was restless, walking or running aimlessly in its cage and striking its most sensitive part—the nose—repeatedly against the wire netting. It reacted to such contact by a leap in the opposite direction, and, rushing headlong, struck its nose against the opposite wall of the cage. As it walked or ran about in the cage, the cat, which under normal conditions is so skillful in evading obstacles in its way and so careful to avoid wet and soppy substances, such as the remains of food and especially excreta, now appeared to be entirely unconscious of these objects, and stepped on them, slipping and falling repeatedly. Its past experiences appeared to have been wiped out, having now no bearing on its present behavior. Its conduct was obviously controlled entirely by the receptors, and any disturbance communicated to them immediately set going the activity of the emotional and coordinated motor mechanisms to their fullest capacity. Summing up the cat's behavior at this stage of the experiment, we have

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the following: ( i ) an exaggerated reaction of the skeletal musculature to disturbances imparted to the receptors; ( 2 ) an exaggerated emotional reaction to such disturbances; ( 3 ) a behavior which was not in correspondence with its previous experiences; and ( 4 ) a behavior which was not suited to its present surroundings. The last two factors are indicative of disorientation both in the past and in the present. In the course of evolution of animals possessed of a cerebrum, the interdependence of these two classes of orientation is of a definite kind and requires elucidation in this place. A decapitated frog exhibits defensive reactions, which to the superficial observer might seem to be adequate; and so did Sherrington's dog ( 7 , p. 288) defend himself against the stimulus simulating the irritation by a flea, after his spinal cord had been severed above the level at which the stimulus was applied. Goltz's ( 1 1 ) dog, with an ablated cortex, though blind and deaf, exhibited signs of fright at the appearance of a frightening object. Barenne's ( 1 2 ) as well as Cannon's ( 1 3 ) decorticated cats manifested defensive reactions by a pugnacious emotional expression. In a certain sense such actions are indicative of an orientation in the present surroundings. It is a fact, however, that by such orientation in the present surroundings, which is independent of past experiences, the animal's reactions are inadequate, and it cannot therefore survive for long. Animals whose cerebral cortex has been removed, do not eat unless food is actually in contact with the inside of the mouth. T h e scratching movements of Sherrington's dogs were ill-aimed, never quite reaching the point of irritation. Deprived of the modifying influence of past experience, the behavior of an animal is like that of the automobile with a certain number of special devices for adjusting its existence to a corresponding number of surrounding conditions. Its functions are fixed and invariable. They are therefore inadequate amidst changing surroundings. The cat whose cerebral cortex has ceased functioning, becomes an automaton, and the number of devices at its disposal for adjusting it to the countless changing conditions in its surroundings are inadequate. Deprived of the experiences which it has acquired during its lifetime, the adult animal reverts to the state of the newborn, except for the greater strength of its muscular, vascular, and glandular reactions. A good example of the difference between an animal whose present behavior is controlled by past experiences and one whose behavior depends upon the kind of disturbance immediately imparted to its receptors is afforded by an observation by Goltz (r 1 ) . A dog, whose cerebral cortex

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had been removed, rejected meat made bitter with quinine, with the invariability of a machine} while his sound dog, very reluctant though it was to taste the disgusting morsel, ate it under the friendly persuasion of his master. The latter dog's past experience was to the effect that the benefit to be derived from complying with a friend's wishes was worth the price. The example of the action of the latter dog, who brought past experiences to bear upon present behavior and for the sake of future benefits overcame the aversion to the bitter meat, is illustrative of a volitional act, as distinguished from the unvolitional one of the first dog, who rejected it. This distinction and its physiological and anatomical significance will be more fully treated in an analysis of the function of the cerebral nerve pathway (fig. i f ) , which descends on the ventrally placed motor cells in the spinal cord and the brain stem (Chapter V, "The Will"). The experiment cited of the behavior of the normal cat, as contrasted with the behavior of the cat whose past experiences had been abolished by a paralysis of its cerebral cortex, exemplifies the manner in which reactions, set going by impulses from the receptor organs, are modified by cortical nerve impulses in correspondence with past experiences. Examples from everyday life illustrative of the effects of past experience on present behavior are numerous and familiar. Objects and conditions with which we have had no previous experience, unless they are an immediate source of pain or satisfaction, cause us no concern j while past experience of the benefit or harm that certain objects or conditions may cause us, calls forth in us corresponding motor and emotional reactions. The sight of a certain gray-colored dirt washed down a mountain gully by rain into the valley below, is productive in the inexpert person of no special motor and emotional reactions. But the expert immediately proceeds to examine it and, having done so, is filled with a sense of joy at having found a treasure of valuable ore, of which he proceeds to possess himself at the cost of labor and privation. The immediate reaction to the given disturbance of his receptors is augmented and maintained by cortical nerve impulses, molded in accordance with his past experiences. And the same example can be turned to illustrate the manner in which the initial reaction may be entirely changed. Thus our man's immediate reaction was to proceed to excavate the ore and to possess himself of more wealth than he already had. But if his past experience is to the effect that such additional wealth cannot afford him additional satisfaction, he will, instead of proceeding to obtain it, leave its acquisition to those of his fellows who may be in need of it.

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The previous example of the expert prospector and of the inexpert person is illustrative of the fact that increasing degrees of orientation in the present are brought about by a proportionate amount of orientation in the past. That the dandy will notice flaws of attire more readily than the person who has been paying only an ordinary amount of attention to dress; that the woodsman will observe markings on trees and on the ground that the city man will not notice, although his senses may be just as sharp or sharper than the woodsman's; that the shoemaker will know at a glance the quality of the shoes and the tailor the quality of the clothes, of which their daily wearer may be unaware, although the acuity of his perception may be just as great or even greater than that of the shoemaker and the tailor, are familiar facts. A story is told of a great zoologist who complimented the cook on the excellence of a roasted fowl served at the table. The cook received the compliment with becoming modesty but informed him that his praise was somewhat misplaced, the meat he had eaten having been rabbit and not fowl. T h e zoologist's past experience with animals prepared for the table was obviously defective. A recent occurrence brought home to me the fact that the extent of previous experience makes for a corresponding degree of recognition. A "head cold" resulted in slight temporary deafness. In the company of a number of English and German-speaking friends, I heard the English distinctly but could not make out the German at all. T h e fact is, my past experience with spoken German is rather meager. The account given of a social evening respectively by an "intellectual" and his wife, illustrates the manner in which special training—past experience of a given kind—affects the function of perception. T h e man spoke of the shallow mentality of the guests, their distorted notions of history, their childish viewpoint of politics and economics, their crude literary tastes, and so forth. His wife spoke with enthusiasm about the elegant furniture, the well-dressed and pretty women, the fine manners and polite bearing of the men, the lively conversation, and the delicious refreshments. A

DEFINITION

OF SENSATION

AND

FEELING

W e see then that re-cognition of any object or condition does not differ essentially from its cognition. For inasmuch as the act of cognizance is subjectively manifested only by dint of a previous familiarity of some degree

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with the particular object or condition, it is equivalent to re-cognizance. Cognition, in other words, implies re-cognition, which is the same as to say that orientation in the present, outside of relatively narrow limits, is not possible without an orientation in the past. W e have already seen that the physiological significance of such orientation in the present and the past is a modification of the nerve impulses which proceed from the receptors, by others which have traversed the pathways of the cerebral cortex and which, in their passage along these pathways, have become modified in correspondence to the manner in which those pathways have themselves been changed by preceding nerve impulses. W e have further seen that after emerging, much changed, from the cerebral cortex, the latter nerve impulses, by their action on the thalamic plexus, either enhance or inhibit the emotion of the vascular, visceral, and glandular mechanisms of the body. It is such nerve impulses which constitute a sensation, in contradistinction to nerve impulses which ascend to the thalamus and which by their effect on the emotional mechanism of that organ are productive of feeling, and to still other nerve impulses which proceed by the shortest routesy which initiate neither sensation nor feeling. T h e subjective experience of sensation is therefore significant of a relatively exact orientation in the past and in the present, while the experience of feeling signifies a relatively vague and small amount of such orientation. It must be borne in mind, however, that a limited amount of orientation in the present and immediate environment only, exists in the entire absence of either sensation or feeling and is therefore outside the sphere of consciousness, while an orientation limited largely to the past is operative in the mental functions of imagery and hallucination. KNOWING

AND

FEELING

It is clear then that the effect of an external disturbance communicated to the receptors is the propagation of nerve impulses which result in an internal disturbance of a certain magnitude and kind. 3 If the nerve impulses in ques3 Lashley ( 1 4 ) has criticized the concept o f the thalamic plexus as the center presiding over the emotions. F r o m what has been said above, it w i l l be seen that an emotion o f the vital capacities may o f course take place at l o w e r levels than the thalamus. T o this extent his criticism is just. Such an emotion, h o w e v e r , although it may be manifested b y a corresponding expression, is not subjectively m a n i f e s t e d by feelings or sensations and is altogether on a smaller scale than w h e n it takes place on the level o f the thalamus. H o w f a r Lashley's other criticisms o f the thalamic theory o f the emotions are just, the student must decide f o r h i m s e l f .

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tion succeed in reaching the thalamus, the greater magnitude of the resulting bodily disturbance constitutes the vague subjective experience known as feeling. If the nerve impulses next succeed in reaching the cerebral cortex, the internal disturbance which signals the external disturbance is there graded and appraised in conformity with past experiences, according to the formula given, with the result of an abatement, an augmentation, or an entire change of the bodily disturbance. W e have seen that it is the relatively exact appraisal of a situation by the cortex which constitutes sensation. As the bodily disturbance which is associated with feeling is initiated before the appraisal of the external disturbance by the cortex, it is obvious that there can be no sensation without feeling. T h e reaction of a stone to the blow of a hammer is brought about by its internal disturbance produced by the external force. T o a person who has learned to understand the reactions of a given stone, it "speaks a various language," which is informative of its particular kind of internal disturbance and of the intensity thereof; and by the kind and intensity of the stone's internal disturbance, he can infer the nature of the external force which caused it. A person is able to understand "the language" of the stone because the reactions of the stone are transmitted to his own body, with the result of a corresponding internal bodily disturbance. If the latter reaches his thalamus, it is indexed by a particular feeling. If the disturbance is then transmitted to his cerebral cortex, it is there more thoroughly analyzed and measured by the standards of past experiences, with resulting sensations of definite kinds and grades, which constitute knowing. Since the nerve impulses produced by the disturbance of the receptor organs can reach the cerebral cortex only by way of the thalamus, where they are productive of feeling, it will be readily seen that knowing cannot possibly exist without feeling. A n awareness of an object, outside of the medium of an emotion of some degree, is therefore a pure abstraction.4 That the degree of permanence of the bodily change resulting from sensory nerve impulses, which is indexed by the mental phenomenon of memory, is in proportion to the degree of the concomitant emotion, is a fact well known to psychologists, as will appear from the following quotation from Pillsbury ( 1 5 ) . Objects that have called out an emotional mood, whether pleasant or unpleasant at the time, gain greatly in their effectiveness for association. Any other 4 From what has been said, it will be easily surmised that although feeling is a function of the thalamus, an awareness o f the particular kind and shade of f e e l i n g is referable to the cerebral cortex.

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impression received at the time, no matter how indistinct it may have been, inevitably recalls the event that excited the emotion, even after a considerable number of years. The witnesses of a tragedy find it for days continually recurring to them. Every tree or stone that bears the slightest resemblance to those that were seen at the time brings back with a rush the whole harrowing scene, and every event of the daily life seems to furnish some resemblance to the scene which is sufficient to recall the complete event. T H E R E L A T I O N OF F E E L I N G AND SENSATION TO T H E SENSORY R E C E P T O R

ORGANS

In ordinary speech, sensation is more or less synonymous with feeling. It is important, for the purpose of the present study, to clarify the features by which they are severally distinguished. The fact is that the established needs of the body, whether inherited or acquired, are not signaled by any definite sensations, although the feelings by which they are signaled are specific for each of the numerous needs. The surrounding disturbances which are productive of the sensations of light, sound, touch, pain, temperature, taste, smell, and so forth, are referable to circumscribed body areas and to definite receptor organs} but the internal disturbances produced by general body needs, such as the inherited and fundamental needs of food, of water, and of procreation} or of the acquired needs, such as reading the newspaper in the morning, of attending on a patient, of voting in elections, or contributing to the charities, or of solving a cross-word puzzle, or of going to a movie, are not signaled by any special set of receptors, and with a few exceptions they are not referable to any special area of the body, notwithstanding the fact that each of these needs is manifested by specific feelings. It is true that certain body needs are frequently accompanied by certain sensations, but not necessarily so. The want of food is frequently accompanied by a painful cramp of the stomach. But the feeling of hunger is not in itself a painful sensation, and a person may be very much in need of nutrition without suffering any pain. On the other hand, a person may have a severe pain in the region of the stomach from other causes than hunger. The want of water by the body is signaled by the feeling of thirst, and thirst is frequently accompanied by dryness of the mouth and throat and a sensation of burning in those parts. But a person may be very much in need of water, with a feeling of thirst, without any burning sensations in the mouth and throat j while one may have a burning sensation in the mouth and throat without being thirsty. Even when certain body needs are referable to limited localities, they

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are not signaled by definite sensations. Except perhaps when the bladder is so overdistended that it is in danger of being ruptured, the need for urination is not signaled by pain, although the feelings by which it is manifested are of a specific nature and are well localized. There is one instance in which it is difficult to distinguish between feeling and sensation—that of the sense of position. T h e receptors in the muscles are the beginnings of the reflex arcs for muscular coordination, and this nerve system, together with the nerve apparatus of balance and with certain tractions on the nerves of the skin, cooperate in producing a sense of the particular position of the body or of a limb at any one time. But the stimulus of the position of the body or of a limb is by no means productive of as definite a sensation as the stimuli of light, or sound, or contact, or pain, or taste, and the subjective experience partakes largely of the diffuse nature of a feeling. And the same is to a certain extent true of the sense of pressure. On the whole, it appears that sensation is most definite when produced by one set of special receptors on the surface of the body, and that it becomes less definite and more of the nature of feeling when more than one set of receptors are engaged in its production, especially so when the receptors are located on the inside of the body. A general body need of a chemical kind would naturally affect a great many different receptors and so could not be signaled by any definite sensation. And this is true as well of a need which can be satisfied by mechanical means, such as the relief of pressure over a wide, though well-circumscribed region. An example of the latter is the need for urination which arises from the pressure within the bladder. A PARTIAL RECONCILIATION OF THE MODERN POINT OF VIEW OF T H E EMOTIONS WITH THE JAMES-LANGE THEORY

What has been said in the foregoing regarding the essential significance of the emotional state as an emotion of the vital capacities—of the visceral and the vascular activities—in order to enable the skeletal musculature to do work, might not seem to synchronize with certain clinical and experimental facts. Outside of the visceral and the vascular activities, the emotional state includes its externalized expression and the subjective feelings associated with it. Lange (16) argued that the feeling of an emotion resulted from the vascular changes involved. 5 James' (17) broader notion of the 6 " T h e physiological difference between pleasure and anger is . . . in the main limited to a difference in the degree of dilation of the bloodvessels and the heightened innervation of

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emotional state included the visceral and the vascular changes, as w e l l as the external expression, as the cause of the f e e l i n g of an emotion. Common-sense says, we lose our fortune [says h e ] , are sorry and weep; we meet a bear, are frightened and run; we are insulted by a rival, are angry and strike. . . . This order of sequence is incorrect, . . . the more rational statement is that we feel sorry because we cry, angry because we strike, afraid because we tremble. . . . Without the bodily states following on the perception, the latter would be purely cognitive in form, pale, colorless, destitute of emotional warmth. W e might then see the bear, and judge it best to run, receive the insult and deem it right to strike, but we should not actually feel afraid or angry. . . . I now proceed to urge the vital point of my whole theory, which is this: If we fancy some strong emotion, and then try to abstract from our consciousness of it all the feelings of its bodily symptoms, we find we have nothing left behind, no "mind-stuff" out of which the emotion can be constituted, and that a cold and neutral state of intellectual perception is all that remains. I t has, however, been shown clinically and experimentally that the expression of an emotion may exist in the absence of any special visceral and vascular activity. Sherrington ( 1 8 ) severed the v a g u s nerves (upper autonomic) and the spinal cord in dogs, thus separating the viscera f r o m the brain. T h e animals' capacity for the expression of the emotions nevertheless remained. Cannon, L e w i s , and Britton

(19)

removed the entire

mid-

autonomic ganglia in cats. Thus [says Cannon (20, pp. 348, 349)] all vascular reactions controlled by the vasomotor center were abolished; secretion from the adrenal medulla could no longer be evoked; the action of the stomach and intestines could not be inhibited, the hairs could not be erected, and the liver could not be called upon to liberate sugar into the blood stream. These extensively disturbing operations had little if any effect on the emotional responses of the animals . . . all superficial signs of rage were manifested in the presence of a barking dog—hissing, growling, retraction of the ears, showing of the teeth, lifting of the paw to strike—except erection of the hairs. . . . T h e absence of reverberation from the viscera did not alter in any respect the appropriate emotional display; its only abbreviation was surgical. Clinical testimony is to the effect that in certain abnormal conditions the particular mode of the expression

of an emotion does not correspond to the

the voluntary muscles. . . . T h e measure o f their strength ceases under the rule o f anger so that their movements become uncontrolled and inaccurate." A characteristic phrase of Lange's epitomizes his theory of the emotions (p. 8 2 ) : " W h e n H e r m a n n von Bremen counts twenty, he relieves the motor part of his brain o f such an amount of blood by this bit of intellectual activity that he no longer feels the impulse to strike."

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feeling of the emotion, that persons who feel sad may laugh, and that weeping may be provoked in pathological cases by trivial causes. Wilson (21) cites a series of pathological cases showing that the feeling of the emotions does not depend on the expression of the emotions: The conclusion in each instance of bilateral facial impairment has been that the patient can readily feel and be acutely conscious of experiencing a particular emotional state such as that associated with hilarity and joy in spite of the minimal expression in the face. Moreover, the facial element may, as in the case of the "snarling smile" of myasthenia, be a positive distortion of the normal movement, yet the feeling is in no degree lessened or altered. A facial diplegia, as one has often seen, may preserve a mask-like countenance and yet be moved by "inward" laughter. Romberg, for example, mentions the complete absence of expressional movement in one of his cases of facial diplegia, and says the patient "was very sensitive of this point, and termed it his greatest misfortune that he was forced to be joyful or sad without making any demonstration of his feelings to his fellow creatures." Similarly, Sir Charles Bell quotes a case from Dupuytren's clinique, that of a girl of sixteen, with facial diplegia, whose countenance bore a serious character, contrasting forcibly with her frame of mind; "she retained her good humour and sometimes laughed heartily . . . as if behind a mask, her face being quite immovable and grave, whilst the emotion and sound of laughter prevailed." Victor Hugo's The Man Who Laughs6 illustrates the opposite fact. Tilney and Morrison (22) have reported 173 cases of pseudobulbar palsy. It is a disease of the cerebrum generally characterized by its sudden apoplectiform onset and paralysis of a number of parts of the body and subsequent partial improvement. In this disease, violent spells of weeping may replace or alternate with the laughter. . . . The emotional tone of the individual undergoes a marked change in fifty per cent, of cases. . . . In a third of the cases the disturbance is characterized by attacks of uncontrollable, prolonged laughter which, as a rule, comes on without any of the usual provocations. The laughter itself is not necessarily expressive of the patient's emotional state and most frequently is inopportune. Its foolish, spasmodic character gives the impression, at first glance, that the patient is feebleminded or demented. In the paroxysms of laughter, the facial expression, even in spite of the voluntary paralysis of the face, is characteristic; the body and limbs shake; in the more severe cases one or both legs may pass into active clonus and to all appearances the patient is convulsed with laughter; yet he may not experience any of the emotions which all of these motions usually combine to express. 6

Read his address to the House of Lords. " I laugh," said he, "that is to say I weep."

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. . . Crying spells occur in a large number of cases. In their general character they resemble the laughing fits. They do not always express the actual emotional state of the patient and are seldom occasioned by the usual provocations. Both laughing and crying spasms occur in many cases. This condition has caused a number of writers to describe their patients as highly emotional, although they have not appeared to recognize the specific character of the symptom. E v e r y physician of experience has had the opportunity of witnessing in patients with injury of the cerebrum attacks of weeping or of laughter provoked by slight or indeed irrelevant causes, such as do not call forth this behavior in normal persons. I have seen a number of such cases. One is worth relating. It is that of an old man who, years before, had sustained an extensive cerebral injury. Attacks of crying could be induced in that man with machinelike regularity by addressing to him a f e w words of sympathy with his condition. I have seen Dr. Frederick T i l n e y demonstrate the emotional behavior of this patient before a large class of medical students. " H e r e is a man who deserves our profound sympathy. H i s condition is most deplorable, indeed, I may say pitiable . .

declared the lecturer,

but he did not finish—the old man burst out in a loud paroxysm of weeping. A remarkable feature of the cases of pathological laughter is that in some of these patients the laughter does not correspond to their subjective experience—to any sense of humor. In normal persons, what is known as a sense of humor and its normal expression by laughing, 7 is provoked by incongruous situations. Some of the patients in question seen by me were aware of their plight, were indeed laden with sorrow, but such was the disorder of their cerebrum that while they wished to give expression to feelings of sadness and depression, the involuntary result was an attack of laughter. Davison and Kelman ( 2 3 ) recently studied fifty-three cases of pathologic laughing and crying. Thirty-three of these came to autopsy. T h e lesions of the brain were of widely different characters. Twenty-six had vascular disease of the brain, the rest included such diseases as multiple sclerosis, tumors located in different parts of the brain, and so forth. Apparently [say the authors], there are pathways which originate in the cortex and which are in intimate connection with the thalamus, hypothalamus, basal ganglia, mesencephalon and facio-respiratory nuclei. A lesion in any of those centers or along the course of the pathways mediating such impulses may account for these responses. 7 Smiling has still another significance; see Chapter X I I , " T h e State of Attention," section on "Imitation."

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Other observations are corroborative of the same fact—that visceral, vascular, and muscular activities are not the sole factors which underlie the feeling of an emotion. T h e administration to persons of drugs which set going the activity of the mid-autonomic nervous system does not result in the feeling of a particular emotion, but rather in a feeling, as they put it, which is like an emotion (20). I have tested this point from another angle. I reasoned that since the activity of the mid-autonomic nerve system subserves the work of the skeletal musculature, a drug which in moderate amounts increases the tonicity of the muscles and in larger amounts tetanizes them, must initiate the activity of the mid-autonomic nervous system with the accompanying subjective experiences. Strychnine is such a drug, of which I took a small overdose. T h e resulting subjective state was indeed of an emotional nature, yet although it was pronounced, I could by no effort of introspection determine what kind of emotion it was. I could not even determine whether it was agreeable or disagreeable. W h e n , upon rising from a comfortable armchair, I made a few rapid strides and was suddenly arrested by a tetany of the muscles of the lower limbs, the emotion was indeed one of slight apprehension, but upon resuming my seat that quickly subsided. T h e definite conclusion at which I arrived regarding my pronounced subjective experience at the time was that it was an awareness, a recognition of the fact that it was similar to feelings experienced before, but which was not like any particular feeling. Re-cognition, however, is a function of the cerebral cortex, while feeling we have seen to be a function of the thalamus. In this particular case, therefore, the subjective experience consisted merely of re-cognition by the cerebral cortex of a similar previously experienced feeling. W e thus have four factors involved in an emotion. ( 1 ) T h e cortical function implied in the cognition or re-cognition of a situation, or the memory of one, which results in certain internal changes. This cognition or re-cognition may be of different degrees of clarity. ( 2 ) T h e feelings which accompany these internal changes, which may be of different degrees of intensity. ( 3 ) T h e bodily changes, or the emotion proper, that is, the activity of the visceral and the vascular organs. (4) T h e expression of these changes, which is partly by the visible alteration in the size of the superficial blood vessels and the secretion of certain glands (for example, the lachrymal and the sweat glands), but mainly by movements of the facial and the skeletal musculature. A normal cat, exposed before a barking dog, exhibits expressions of the

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emotions of fear and rage, which are undoubtedly accompanied by the corresponding feelings and certainly by the visceral changes elucidated by Cannon and his coworkers. But those who have watched a domestic cat gradually change its attitude of fear and hostility toward a house dog, by dint of constant association, must be convinced of the fact that it is the memory of certain experiences which evokes in it the defensive and offensive reaction toward a strange dog (conditioned reaction). A n d it is reasonable to assume that it is the memory of these experiences which evokes in the cat deprived of the mid-autonomic nerve system all the defensive and offensive reactions of which it is still capable, including the attendant feelings. T h e particular feelings attendant on the visceral response to the action of certain drugs are feelings of an unfamiliar kind of emotion. T h e y are therefore recognized by the cerebral cortex as being similar to but not like any emotion previously experienced. A remark made by Dana (24, pp. 637, 63 8) throws a flood of light on the problem of dissociation of the feeling of the emotions from their expression. A person [says he] may have palpitation of the heart, or a sense of faintness, or tremor, or sweating without experiencing any emotion of fear or apprehension, unless finally the idea that he is in physical danger comes to his mind. This fact is explained by various psychologic mechanisms. It seems most reasonable to suppose that when a palpitation is felt, the emotion of fear develops because an association process arouses an idea of illness, and this causes an emotion of fear. The mechanism of an associated conditioned reflex may also be effectively invoked. It will be readily gathered that the last remark of Dana's implies also the proposition that although a person or an animal may be disabled from mobilizing the forces of the body for the purpose of overcoming an emergency—disabled from making use of the essential machinery of the emotions — t h e memory of past experiences with a condition which threatens clanger will nevertheless evoke the feelings and the expression of the corresponding emotion. T h e latter explains the fact that the removal of parts of the autonomic system did not prevent the mutilated cats from the expression of fear and rage to the extent of their physical ability. W e have seen that the removal of the cerebral cortex does not deprive the animal of the operation of the emotions, and that the vascular and the visceral changes, as well as the expression of the emotions, may take place in the absence of the cortex, except that under such circumstances they are not suited to the surrounding conditions—that is to say, they are not modi-

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fiable by past experiences. W e have also seen that the severance of the spinal cord, of the upper autonomic nerve fibers, and of the entire midautonomic ganglia does not deprive the animal of the expression of the emotions. Between the cerebral cortex above and in front and the brain stem and spinal cord below and behind, are the thalamus and the hypothalamus, which contain the highest centers of the autonomic system for the regulation of the vital activities. In an effort to discover the highest seat for the expression of the emotions—that is, the nerve centers which preside over their f u l l p l a y — B a r d (25) removed in animals successive levels of the brain (fig. 4 ) . H e found that upon reaching a level imme-

Fig. 4. D I A G R A M O F C A T ' S BRAIN ( A F T E R

BARD)

"Sham rage" follows section in planes A or B, but not after section at C.

diately below the thalamic structures the full expression of the emotions could no longer be evoked. It must be borne in mind, however, that the facts regarding the emotions gathered from clinical observations and from operative laboratory experimentation of the kind cited, have a bearing only on the remaining functions of the persons or the animals mutilated by disease or operation. T h e biological significance of the emotional state in the sound animal is admitted by all to be the activity of the visceral and the vascular organs in supplying the skeletal musculature with the energy necessary for their work in emergencies. In the normal state, the index of the intensity and the kind of such activity of the visceral and the vascular organs is a corresponding intensity of the feeling of an emotion, which is the function of the thalamus, while the cognizance and re-cognizance of that state, with different degrees of clearness, is the function of the cerebral cortex. It will naturally be asked whether a destruction of the thalamus by disease or by experimental procedure, which would leave the cortex intact,

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might abolish the feelings and the expression of the emotions while leaving the memories of these intact. T h e answer is that such gross destruction of the thalamus deprives the cortex of incoming sensory impulses and so of the ability to perceive the situation which would ordinarily be productive of a particular emotion as well as of the feelings associated with it. There is, however, one condition which, while it greatly reduces the feelings and the expression of the emotions, spares the memories of such feelings and of such expressions. It is the "cold and neutral state of intellectual perception" of the familiar disaster of old age. SUMMARY

1. T h e cerebrum is an integral part of the body. A l l conditions which affect the body have a corresponding effect on the cerebrum, a number of them being there indexed by the subjective experiences of feelings and sensations. 2. Since underlying every muscular reaction there is an activity of the vital organs for furnishing the muscles with the material for their work and for the removal of waste products, an emotion of the vital capacities may take place at any level of the central nervous system. 3. At successively lower levels of the central nervous system the reactions of the body are marked by increasing degrees of fixity and invariability, and the emotion of the vital capacities which underlies them is increasingly weak. Below the thalamic level such reactions and such emotions are not productive of any subjective experiences. 4. So far as we know, subjective experience of any change in the body first appears at the level of the thalamus in the vague form of awareness known as feeling. A t that level stimuli are not evaluated in the light of past experiences. T h e y are therefore not graded and are poorly localized; the threshold of stimulation is high, but any stimulus above the threshold strength is productive of a widespread reaction and of an intense, although vague, subjective experience of feeling. 5. A t the level of the cerebral cortex, stimuli are evaluated in the light of past experiences. In physical terms, this fact amounts to a modification of succeeding nerve impulses in their passage through the nerve pathways of the cerebral cortex, in correspondence with the modification undergone by these pathways as the result of the passage of preceding nerve impulses. Stimuli at this level are therefore graded and localized by a process of their correlation with similar experiences in the past. T h e accompanying subjective

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experience is that of sensation, which, unlike feeling, is graded not in terms of intensity, but in terms of clarity and accuracy. 6. T h e effect of cerebral nerve impulses on the thalamic mechanism is either to enhance or to subdue the strength of the reactions set going by the latter, as well as the degree of intensity of the accompanying feelings, in correspondence with past experiences. 7. T h e fact that a correct response to a situation is possible only when the latter is appraised in the light of past experiences, makes the act of cognition, as it is ordinarly understood, equivalent to re-cognition. T h e psychological significance of this fact is that increasing degrees of orientation in the present and immediate surroundings 8 are brought about by a proportionate amount of orientation in the past. 8. T h a t activity of the cerebral cortex which consists in the subjective experience of sensation is therefore significant of relatively exact orientation in the present and in the past; while the thalamic function of feeling is significant of relatively vague and limited orientation. Both feeling and sensation are indices of corresponding bodily states. 9. An emotion includes the following four factors: ( r ) the cognition or re-cognition, or the memory, of a certain situation, the act resulting in certain internal disturbances implied by the subjective experience of sensation, which may be of different degrees of clarity; ( 2 ) the feeling which accompanies the internal disturbance, which is graded in terms of intensity; ( 3 ) the internal disturbance itself, that is, the activity of the visceral and vascular organs, which is the emotion proper; ( 4 ) the expression of these changes by muscular movement or in other ways. T h e inclusion of these four factors in the concept of the emotional state reconciles the James-Lange theory with the modern viewpoint of the emotions. REFERENCES 1 . K e n n e d y , F o s t e r . " E p i l e p s y a n d the C o n v u l s i v e S t a t e . "

chiat., 2.

V

(1923),

Arch, of Near, and Psy-

9.

B r o w n , T . G r a h a m . " O n the N a t u r e of the F u n d a m e n t a l A c t i v i t y of the N e r v ous C e n t e r s ; t o g e t h e r w i t h a n A n a l y s i s of the C o n d i t i o n i n g of R h y t h m i c A c t i v i t y in P r o g r e s s i o n , a n d a T h e o r y of the E v o l u t i o n of F u n c t i o n in the N e r v o u s S y s tem."

Journ. Physiol.,

XLVIII (1914),

18.

It w i l l be easily seen that an awareness of the surroundings which do not immediately affect the sensory receptors constitutes an orientation in the past, the person or the animal being aware of them only f r o m past experience. 8

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IOI

3. Clark, W . E . LeGros. " T h e Structure and Connections of the Thalamus." Brain, L V ( 1 9 3 2 ) , 406. 4. Roussy, Gustav. "Thèse pour le doctorat en médicine." Paris. 1907. Published in Faculté de Médecine de Paris Thèses, 1906-7. 5. Head, Henry, and Gordon Holmes. "Sensory Disturbances from Cerebral L e sions." Henry Head. Studies in Neurology, I I , 533. London, Oxford University Press, 1920. 6. Lucas, Keith. T h e Conduction of the Nervous Impulse. London, Longmans, Green and Co., 1 9 1 7 . 7. Sherrington, C . S. T h e Integrative Action of the Nervous System. London, Constable and Co., Ltd., 1906. 8. Economo, Constantin von. T h e Cytoarchitectonics of the Human Cerebral Cortex. Trans, by S. Parker. London, Oxford University Press, 1929, p. 23. 9. Rosett, Joshua. Intercortical Systems of the Human Cerebrum. N e w York, C o lumbia University Press, 1933. 10. Rosett, Joshua. "Epilepsy as an Exaggerated Form of Normal Cerebral Inhibition." Amer. Journ. Psychiat., X ( 1 9 3 1 ) , 673. 11. Goltz, F . " D e r Hund ohne Grosshirn." Pflüg. Arch. f. d. ges. Physiol., L I ( 1 8 9 2 ) , 570. 12. Barenne, Dusser de. "Recherches expérimentales sur les fonctions du système nerveux central, faites en particulier sur deux chats dont le néopallium avait été enlevé." Arch, néerl. de fhysiol., I V ( 1 9 2 0 ) , 3 1 . 13. Cannon, W . B., and S. W . Britton. "Studies on the Conditions of Activity in Endocrine Glands. X V . Pseudaffective Medulliadrenal Secretion." Amer. Journ. Physiol., L X X I I ( 1 9 2 5 ) , 283. 14. Lashley, K . S. " T h e Thalamus and Emotion." Psychol. Rev., X L V (Jan., 1 9 3 8 ) , No. i . 15. Pillsbury, W . B. Attention. New York, T h e Macmillan Co., 1908, p. 103. 16. Lange, Carl Georg. T h e Emotions. Trans, by Istar A . Haupt from the German by H. Curella. Baltimore, Williams and Wilkins Co., 1922, p. 52. 17. James, William. Principles of Psychology. 2 vols., N e w York, Henry Holt and Co., 1902. Vol. II, Chap. X X V , " T h e Emotions," pp. 442-85. 18. Sherrington, C. S. "Experiments on the Value of Vascular and Visceral Factors for the Genesis of Emotions." Proc. Roy. Soc. of London, Series B, L X V I ( 1 9 0 0 ) , 390. 19. Cannon, W . B., J. T . Lewis, and S. W . Britton. " T h e Dispensability of the Sympathetic Division of the Autonomic Nervous System." Boston Med. and Surg. Journ., C X C V I I ( 1 9 2 7 ) , 514. 20. Cannon, Walter B. Bodily Changes in Pain, Hunger, Fear and Rage. N e w York, D . Appleton and Co., 1929. 21. Wilson, S. A . Kinnier. "Some Problems in Neurology. II. Pathological Laughing and C r y i n g . " Journ. of Neur. and Psychopath., I V ( 1 9 2 4 ) , 299. 22. Tilney, Frederick, and J. Francis Morrison. "Pseudo-Bulbar Palsy, Clinically

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and Pathologically Considered, with the Clinical Report of Five Cases." Nerv. and Ment. Dis., XXXIX ( 1 9 1 2 ) , 505.

Journ.

23. Davison, Charles, and Harold Kelman. "Pathologic Laughing and C r y i n g . " Read before the Sixty-fourth Annual Meeting of the American Neurological Association. 24. Dana, Charles L . " T h e Anatomic Seat of the Emotions: A Discussion of the James-Lange T h e o r y . " Arch, of Neur. and PsychiatVI ( 1 9 2 1 ) , 634. 25. Bard, Philip. " A Diencephalic Mechanism for the Expression of Rage with Special Reference to the Sympathetic Nervous System." Amer. Journ. Physiol L X X X I V ( 1 9 2 8 ) , 490.

CHAPTER

FIVE

THE WILL The manner in which the cerebral cortex controls the activity of the thalamus, thus bringing past experience to bear upon the intensity of the emotions, was dealt with in the preceding chapters. The fact was mentioned that the cortex likewise exercises control over the skeletal musculature, thus bringing past experience to bear upon overt behavior. This latter fact will be briefly discussed in the present chapter. N O N - V O L I T I O N A L AND VOLITIONAL ACTS

Few subjects have been more abused in discussion than that of the will. Many a smug volume could be filled with a recital of the nonsense with which it has been weighed down throughout the ages. Leisurely philosophers, speculative psychologists, mercenary charlatans, and religious fanatics have alike done their best to bury it under a mountain of mystery, mysticism, and divinity. An examination of the famous controversy between the adherents of the hypotheses of free will and predestination could alone keep one busy a lifetime. It will therefore be best to let sleeping dogs lie and to proceed with an examination of the facts involved. A few familiar examples will clarify what constitutes, from a common sense point of view, an act of the will. It is agreed by all that such acts as eating when one is hungry, drinking when one is thirsty, lying down to rest when one is tired and sleepy, do not involve an exercise of the will; and what is true of the positive phases of these acts is likewise true of their negative phases—of abstaining from food when one is satiated, from drinking when one is not thirsty, or not lying down to rest when one is on the alert and energetic. Let us now reverse the relation involved between the state of the body and the ensuing act, or abstinence from the act. A man forces himself to eat when he is satiated, as was for example the case in the North American Indian eating bouts; he forces himself 1 to drink when he is not thirsty and 1

In each case it must be himself. If he is forced to drink by someone else, as was a common preliminary in the process of inquisition into one's faith in Spain ( i ) , the act is of course not a volitional one.

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drinking is painful j he lies still in spite of the fact that he has a desire for muscular exercise} he abstains from eating, although he is hungry and food is accessible^ he abstains from drinking, although he is thirsty and water is before him; he abstains from sleeping, although he is tired and sleepy— those are agreed to be volitional acts. A volitional act is thus, in the first place, one which is not calculated to satisfy an immediate positive or negative need of the body and which is, because of that, correspondingly difficult. Since every act of the normal animal subserves the satisfaction of some bodily need, and since a volitional act is not calculated to satisfy an immediate need, that need must be more or less distant. In other words, a volitional act has a more or less distant motive. We may now proceed a step further and inquire into the nature of that motive. T H E M O T I V E OF A VOLITIONAL A C T

In the course of industrial and commercial evolution, it was discovered that coercing people to work under the whip of an overseer was an inefficient procedure. The worker's activity was prompted by the cracking of the whip, but immediately the overseer turned his back, activity slackened or ceased. Every act of volition being prompted by a more or less distant motive, the latter was then resorted to, instead of the whip, and, the substitution having proved successful, volitional or voluntary labor was generally substituted for unvolitional or involuntary labor. And the great progress of industry and commerce since voluntary labor, motivated by the more or less distant prospect of the means of livelihood, has been substituted for the whip of chattel slavery, testifies to the greater efficiency of the volitional effort, as compared with effort which does not involve the exercise of the will. We are now prepared to trace the genesis of a volitional act. ITS GENESIS

The motive for an act must be distinguished from its genesis. The implication of motive is a future occurrence, and it is plain that a present act cannot have its genesis in a future event. A future event at this moment becomes, however, an event of the past an hour from now. The following examples illustrate the fact that every volitional act has its genesis in the consequences of similar acts in the time past. A physician prescribes for his patient an ill-tasting concoction, and the patient, in spite of his aversion, drinks it. Asked why he drinks the disgust-

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ing draft, his reply is that he is ill and that from past experience he is convinced that Dr. X is a good physician who will cure him if he follows directions. This is an example of the genesis in past experience of a positive volitional act. Take now an example of a negative volitional act. I offer a friend a cocktail and he refuses to drink it. Upon being asked the reason for his abstinence, he assures me that he has a strong desire to drink it, and but for his past experience that it makes him ill, he would gladly drink it. No matter what volitional act, positive or negative, we may select, we shall always find that its genesis lies in past experience, and that its motive is some real or alleged future good, or the avoidance or the alleged avoidance of future harm. I say "real or alleged." For past experience which is gained by false representation or symbolism may be faulty, and the motive consequently a false motive. Thus a man's past experience may be to the effect that the act of murder, motivated by the acquisition of money, will be to his future benefit. The murder in that case is, to be sure, a volitional act on his part, but the probability is that instead of resulting in his future good it will result in his being hanged. What is true of human beings is likewise true of the higher animals. Goltz's ( 2 ) intelligent dog, already mentioned in a preceding chapter, ate meat made bitter with quinine in spite of his normal aversion for it. His past experience was to the effect that to please his friend was, on the whole, productive of future benefits. D E F I N I T I O N OF A V O L I T I O N A L A C T

On the basis of these considerations, we may formulate a definition of a volitional positive or negative act as being one which, although it is difficult or disagreeable, is nevertheless executed because past experience is to the effect that it is productive of more or less distant future benefits, real or alleged. With this definition of a volitional act, we may undertake to discover the bodily mechanism by which past experience determines present activity for the sake of some future end. T H E P Y R A M I D A L T R A C T AS T H E N E R V E P A T H W A Y FOR T H E

CONDUCTION

OF T H E W I L L

A patient complains of inability to move his right leg. Upon examining the muscles of that limb and their innervation, the young medical student

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finds them as healthy and as well nourished as those of the patient's left limb. H e tests the reflexes of the affected leg and finds that the muscles can contract, and that the antagonists on the opposite sides of the joints cooperate in the normal way for the production of reflex movement. The young student reports the state of affairs to his superior, who forthwith visits the patient and orders him to raise the right leg. " T h e report is," says he, "that almost any stimulus is effective in causing the muscles of your right leg to contract and to relax in the normal way. Now try to move that leg." The patient remaining obdurate, the physician attempts persuasion. "Don't you know from past experience," says he, "that it is for your future good to follow my directions? Surely you have not forgotten that I have on many occasions cured you of your ailments?" T h e patient's reply is that from past experience he is convinced of the good that will come to him by following the physician's directions, but that although it is true that almost any stimulus is effective in causing his right leg to move, there is one which is in this respect utterly ineffective, and that is the stimulus of his own will. In the course of time the patient dies. A post-mortem examination reveals the entire nervous system to have been sound, with one small exception. The nerve tract which descends from the cerebral cortex into the spinal cord (fig. i f ) , the pyramidal tract, was injured in part—the part which plays upon the motor cells innervating the muscles of the right leg. Consequently, the nerve impulses which are conveyed from the storehouse of memories of past experiences in the cerebral cortex, by way of the nerve tract in question, could not reach the motor nerve cells which innervate the right leg. Therefore, although the patient's past experiences were well preserved, they could not be made to bear on the muscular activity of his right leg. The patient was therefore powerless to move that limb by means of his will. Another patient was afflicted by inability either to contract the facial musculature or to move any of his four limbs by the power of his will. H e , too, died. A post-mortem examination revealed that nearly the entire pyramidal tract on both sides had been severed by a lesion at a high level. Therefore, although the storehouse of past experiences in the cerebral cortex of that patient remained intact, he could not bring his will to bear on the activity of his face and limbs. Many thousands of such patients have been observed while living, and their bodies examined after death, with invariably the same findings. The

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conclusion is therefore justified that the nerve tract which descends from the cerebral cortex to the motor cells in the brain stem and the spinal cord— the pyramidal tract—normally conducts the nerve impulses from the storehouse of memories of past experiences in the cerebral cortex to the motor cells which innervate the muscles. They are the nerve impulses which constitute the will. What is true of the inability of persons afflicted by an interruption of the pyramidal tract to execute movement by an effort of the will, is likewise true of their effort to abstain from movement. This is plainly shown by the following experiment. The knee jerk, which follows a blow on the patellar tendon, is one of the most constant reflexes. By a course of training, however, I succeeded in diminishing in some and in abolishing in other normal persons the patellar reflex, for a time. This was likewise true of the same reflex on the normal side of persons afflicted with injury of the pyramidal tract on the opposite side. But no amount of training was effective in diminishing in the least the patellar reflex on the side on which the pyramidal tract was interrupted. The movement of the leg which followed a blow on the patellar tendon, and other modes of stimulation, was utterly independent of the person's will to suppress it. Therefore, the will could not be mobilized, in this case, for the process of training, or learning. T H E R E L A T I O N OF T H E W I L L TO T H E C E R E B R A L C O R T E X

Still another class of patients whose behavior is independent of the will is corroborative of the argument that the will consists of the process of bringing past experience to bear upon present behavior, for the sake of some future real or alleged good. These are persons whose pyramidal tract and whose muscles, together with their innervation, are sound, but who have some defect of the cerebral cortex. In these persons the storehouse of memories of past experiences is largely absent. Their behavior is, in consequence, like that of the infant or the young animal, since they are lacking in the power of will to a corresponding degree. From the point of view of experience, such persons have no past and, having no past, they have nothing to bring to bear on their future. SUMMARY

1. T h e will is a term signifying the mental act of bringing past experience to bear upon present behavior for a more or less distant motive.

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2. Since a volitional positive or negative act is not calculated to satisfy an immediate need, its execution is for that reason disagreeable or difficult. 3. T h e material of the will being the memory of past experiences, it is a function of the cerebral cortex. 4. T h e pyramidal nerve tract conducts nerve impulses, modified by memories of past experience, from the cerebral cortex to the motor apparatus of the brain stem and the spinal cord. That nerve tract is therefore the pathway of the will. REFERENCES

1. Lea, Henry Charles. History of the Inquisition of Spain. N e w Y o r k , T h e M a c millan Co., 1922, p. 19. 2. Goltz, F. " D e r Hund ohne Grosshirn." Pflug. Arch. f. d. ges. Physiol., L I ( 1 8 9 2 ) , 570.

CHAPTER SIX NERVE

SIGNALING

Not the microscope nor the electric current nor any other physical means has enabled us so far to read in the nerves of the dead brain the contained record of the animal's experiences. A faint suggestion of the nature of some of the changes in nerves brought about by the passage of nerve impulses is perhaps afforded by the process of myelination. In the course of their development, the units of some of the nerve systems are covered earlier than others with a myelin sheath. Flechsig ( i ) has observed that among the first to be coated with myelin are the nerve pathways which conduct impulses set going by the stimuli of gravitation and of sound. T h e former are parts of the nervous machinery for the maintenance of a bodily posture against the attraction of the earth, which tends to overthrow it. T h e latter is the nervous apparatus of hearing. It will be observed that the stimulus of gravitation affects the fetus through the body of the mother, while sounds are capable of being propagated through the tissues of the body. T h e last to myelinate are the association systems of the cerebral cortex—the nervous machinery of memory and recall. A very suggestive observation of Flechsig's (2) is the following. A t birth the optic nerve is unmyelinated and the newborn baby is therefore blind. Myelination begins soon after light strikes the retina and is complete within a few days. A n d this is true whether the baby is born at term or at seven months. Flechsig points to the fact that the ripening of the nerve is brought about under the stress of nerve impulses —that experience results in an organic change in a nerve. But that is as much as we know. M y own investigation ( 3 ) of one hundred adult brains, with the view of discovering whether the total quantity of meylin is in proportion to the degree of intellectual development, has not been productive of any definite conclusions. In our ignorance of the record wrought in nerves by the animal's experiences, we are somewhat comforted by the knowledge of the code in which those experiences are signaled from the receptors along the nerves. T h e works of Lucas ( 4 ) , of Adrian ( 5 ) ( 6 ) , of Erlanger and Gasser ( 7 ) , and of a great number of other investigators have shown that the signaling

no

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through nerves is a monotonous repetition of the nerve impulse. If the application of a stimulus to a nerve fiber is strong enough to set going a nerve impulse, any increase in the strength of the stimulus will not result in a stronger impulse. This is the famous all-or-none principle of nerve conduction. T h e reason for the greater effects of stronger stimulation of a nerve trunk is simply that the trunk contains a large number of nerve fibers, and the stronger stimulus reaches a greater number of them. T h e signaling along nerves consists, then, of nerve impulses. In this respect it somewhat resembles the Morse telegraph code, except for the fact that a variety of specialized receivers and other devices make the signaling through nerves considerably more efficient. A familiar analogy will be helpful to an appreciation of the efficiency of that code. It is the business of an ideal government to coordinate the activities of the inhabitants in the different parts of the country in such a way that the means of livelihood shall be accessible to all. If a part of the population is engaged in the production of wheat, another in the production of shoes, a third in that of quinine, and a fourth in the raising of cattle, it is obvious that enough of these articles must be produced to supply the entire population, but not a great deal more than enough. In order to achieve the ideal state of an abundance of supplies with the least amount of effort, the several departments of the central government must be kept informed at regular intervals regarding the activities of the different parts of the population. By telegraphing in the Morse code, the shoemakers could communicate with the government shoe department as follows: " W e have produced today 1,000 pairs of shoes." It will be seen at once that a number of words in this message are superfluous. Since the business of the shoemakers with the shoe department is about nothing but shoes, they might as well telegraph, " W e have produced today 1,000 pairs." T h e message still contains too many words. Shoes always go by pairs, and the information wanted by the department in question is regarding production only, and that from day to day. A message reading " 1,000" would therefore be understood by the shoe department as "Produced today 1,000 pairs of shoes." T h e same department, however, takes care of the different qualities, styles, and sizes of shoes. W e say, for example, Grade A 1. Instead, we could just as well say 17, or any other number that we might agree on, to represent A 1. And in the same manner that quality may be expressed by a number, so could style and size, the particular number corresponding to a given style having been agreed upon beforehand. Thus a message reading

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" 1,000 17 93 n " could, by agreement, signify the number of pairs of shoes, their particular quality, style, and size. Actually, however, the signaling through nerves, when descriptive of even the simplest object or condition in the surroundings, requires many more than four factors. There is, however, ample provision for such detailed description. Outside of the limitation that each sensory area of the cerebrum receives only one category of sensations, the signals are capable of endless modification, by the following means: ( 1 ) A stronger stimulus applied to a receptor organ results in a larger number of nerve impulses being propagated within a given time ( 5 ) . ( 2 ) A larger number of sense receptors, stimulated at the same time, sets going nerve impulses in a larger number of nerves, thus making for a larger total number of nerve impulses. ( 3 ) A r rived at the central nervous system, impulses propagated from a number of receptor organs may, by mutual interference or mutual enhancement (summation at the synapse), result in modified effects. (4) A t points where the nerve impulses are relayed from the end of one nerve to the beginning of another nerve (at the synapse) in the course of the nerve pathway, a modification of the signals is especially apt to take place. A t those points impulses propagated along a single nerve fiber may be transmitted to a number of nerve fibers, with a consequent multiplication of effects; while impulses flowing along many nerve fibers may be transmitted to a single nerve fiber, with the result that a number of impulses may be eliminated and their timing changed. ( 5 ) A t such points the particular chemical state of the body at the time is especially effective in bringing about changes in the number and the timing of nerve impulses. ( 6 ) In certain instances the result of the flow of impulses across the synapse, or across the junction of a nerve with the tissue which it innervates, is productive of chemical changes (such, for example, as the appearance of acetylcholine, sympathin, esterase, and so forth), whose action modifies the further effect of these impulses. ( 7 ) Certain nerve fibers are capable of transmitting a greater number of nerve impulses within a given time than are others. (8) There are a number of other conditions, which need not be enumerated here, which make for a variation of the signals. Since by far the largest part of the cerebrum consists of very short nerves, it contains, in the course of the numerous cortical association pathways, a vast number of points of contact between the endings of some nerves and the beginnings of others, with correspondingly vast potentialities for signaling minute variations in the external and the internal conditions.

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SUMMARY

1 . T h e m a n n e r in w h i c h experiences are r e c o r d e d in n e r v e s is so far unknown. 2. E a c h class of receptor o r g a n s is capable of s i g n a l i n g to t h e cerebrum o n l y a s i n g l e c a t e g o r y of i n t e r n a l o r e x t e r n a l disturbances. 3 . D i s t u r b a n c e s i m p i n g i n g on t h e receptor o r g a n s are s i g n a l e d

along

n e r v e s b y m e a n s of a m o n o t o n o u s repetition of n e r v e i m p u l s e s , w h o s e d i f f e r e n t t i m i n g a n d rate of repetition a r e , h o w e v e r , a m p l y sufficient f o r dist i n g u i s h i n g a v a s t v a r i e t y of e x t e r n a l a n d internal conditions. REFERENCES

1. Flechsig, Paul. Anatomie des menschlichen Gehirns und Rückenmarks auf myelogenetischer Grundlage. Leipsig, Georg Thieme, 1920. 2. Flechsig, Paul. Gehirn und Seele. Leipsig, 1896, p. 53. 3. Tflney, Frederick, and Joshua Rosett. " T h e Value of Brain Lipoids as an Index of Brain Development." Bull, of the Neur. Inst. ofN. Y., I (Jan., 1 9 3 1 ) , p. 28. 4. Lucas, Keith. T h e Conduction of the Nervous Impulse. London, Longmans, Green and Co., 1 9 1 7 . 5. Adrian, E. D . T h e Basis of Sensation. T h e Action of the Sense Organs. New York, W . W . Norton and Co., 1928. 6. Adrian, E . D . T h e Mechanism of Nervous Action. Electrical Studies of the Neurone. Philadelphia, University of Pennsylvania Press, 1932. 7. Erlanger, Joseph, and Herbert S. Gasser. Electrical Signs of Nerve Activity. Philadelphia, University of Pennsylvania Press, 1937.

CHAPTER SEVEN T H E EFFECT OF INJURIES OF T H E

ASSOCIATION

SYSTEMS THE ELEMENTS OF THE MEMORY OF A SITUATION T h e elements of the memory of a situation consist of a given number of sensations of different degrees of clarity, and of feelings of different degrees of intensity, organized in a certain way. Touch, resistance to movement (muscle sense), temperature, light, sound, taste, smell, gross vibration, and balance are names for wide categories of subjective experiences produced by impacts of surrounding objects and conditions upon our bodies, or of the parts of our body upon one another. Not only does each category of subjective experience contain a large number of classes, and not only is each class resolvable into units of different quality, but any two or more of these units experienced simultaneously, or nearly simultaneously, make for a different, more or less novel, state of consciousness. T h e so-called "objective" tests of the sensations generally employed by physicians in examining a patient, are only grossly valid. T h e application to the tongue of sour, bitter, sweet, and salty substances elicits only four out of a multitude of different states of consciousness in the category of taste. Different concentrations of a sweet substance are appreciated as of correspondingly different degrees of sweetness and as of different intensities of the same feeling of taste. Yet the same concentration of a sweet substance is of different degrees of sweetness to the taste of the same person at different times; and it is of different degrees of sweetness to the tastes of different persons at the same time. Admixtures of other substances make for a modification of the sweet taste, which is expressible only in terms of the bodily reaction to it, such as a "cloying," a "disgusting," a "sickening" sweet taste, or in terms of the causative substance, such as the sweet tastes respectively of sugar, of honey, of saccharine, of the salicylate of soda. T h e simultaneous or nearly simultaneous contact of a substance with the

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receptors of two or more different categories of sensation makes for a further multiplication of different states of consciousness. A familiar example is the difference in the taste of food when the receptors of smell have been incapacitated by the congestion of the mucous membrane of the nose by a "cold in the head." The juice of the watermelon is insipid and, to most people's taste, rather disagreeable, the agreeable taste of the watermelon pulp being due to the effect of its peculiar consistency on the touch corpuscles of the mouth. Chemically, cane sugar, rock candy, and sugar fleece are exactly the same, their different sweet tastes being due to their different degrees of solubility and to the effect of their consistency on the touch corpuscles. The taste corpuscles are located on the tongue, yet persons afflicted with the calamity of a denture which covers the hard palate complain that food "has lost nine-tenths of its taste." Even conditions prevailing at a distance may make for changes in the taste of the same substance. By the action of these conditions on the receptors of light or sound or smell and by the correlation of the sensations and feelings produced by them with memories of certain situations, widespread changes are set going in the body, such that the taste of a substance which is ordinarily agreeable may become disagreeable, or the reverse. Certain changes in the body itself are productive of the recall of certain experiences, and these memories may result in the change of the taste of a given substance. It will be seen, therefore, that the sensation of a given taste is not an isolated experience of an absolute nature, but that its character depends on its spatial and temporal relations to other subjective experiences. Even such a crude and simple subjective experience as pain is remembered only in the spatial and temporal relations of the object or condition causative of the pain to the part of the body affected, or in terms of the bodily reaction to it. A person complaining of a pain describes it as a cramping pain in a part of the abdomen or in a muscle; a pain in a bone, as if a gimlet was boring into it; a pain in a limb, as if someone twisted it; a constricting pain in the chest, as if it were squeezed in a vise; a cutting pain in the back, as if inflicted with a sharp blade; a rasping pain, as if a saw had gone over the flesh; a stabbing pain in the side, as if a pointed instrument had been pressed against it; a pain like a toothache, and so forth in an almost infinite variety of relations of time, space, clarity, and intensity, expressible only by means of comparisons and other figures of speech. If that be the case with such simple sensations and feelings as taste and pain, what are we to say regarding such complex sensations, and the feelings

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accompanying them, as vision and hearing? How few are the objects which to the sense of vision appear to be in every respect alike; how few are the sounds which to the sense of hearing appear to be identical! Yet even the memories of those that are nearly alike, at the time they are experienced, become different, owing to the different internal and external conditions prevailing at a later period. Any one sensation or feeling is thus resolvable into units of different qualities, whose value is determined by the spatial and temporal relations of the particular unit to other units of the same category and to units of other categories of subjective experience. The value in question is further subject to the internal and the external conditions existing at the time. The different internal and external conditions prevailing at a later date still further modify the value of the memory of any such experience. One need only be reminded of the homely fact that no pie tastes like "the pie that mother used to make" to be convinced of the truth of the last proposition. The sensory effect of any one situation being so complex, and the memoryrecords of situations possessed by an adult of average intelligence being innumerable, the question regarding the location of the repository of the memory-records in the body becomes one of great interest. T H E REPOSITORY OF M E M O R Y

Since the memory of any one whole situation implies memories of a number of sensations and feelings related to one another in certain ways, we might for that reason alone exclude the sensory receptive areas of the cerebrum from serving as the repositories of composite memories. There are, however, still other reasons for this exclusion. The destruction of a sensory area in the adult or the adolescent, although it abolishes the reception of the corresponding sensation, does not abolish the memories of that sensation. We shall see, indeed, that the destruction of such an area, far from abolishing it, sets going the memories of that sensation in the form of hallucinations. There remain, therefore, the association systems of the cerebral cortex. Suppose we take a simple object, say an apple, and attempt to discover where, in the association systems, it is recorded. We remember an apple by its particular shape, color, weight, consistency, odor, taste, and so forth. Therefore, it will be agreed, in the first place, that the apple is represented in memory by all categories of sensation, together with their accompanying feelings. Suppose then that we locate a cell in the association systems with which are connected the nerves extending from every sensory receptive area

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of the cortex. It is plain that such a cell will no more contain a record of the apple than it might of a peach or of a horse, for the simple reason that all of the sensations are represented in the memory of a peach or of a horse, as well as in that of an apple. Suppose now that the receptive area of vision is connected with a cell in the association areas which admits only of the registry of the shade of the red color of the particular apple; that the area of touch is connected with a cell which admits registry of the consistency of that apple only; that the receptive area of taste is connected with a cell which admits registry of the particular taste of that apply o n l y ; and that these three cells are conneced with a fourth cell in the association systems. W e might suppose that that cell contained the memory-record of the particular apple. If this were the case, the destruction of that cell would result in the abolition of the memory of the apple, while all other memories remained intact. Such, however, is not at all the case. T H E I N F E R E N C E S D R A W N FROM T H E

APHASIAS

T h e fact is that injury of the association systems results as follows: ( i ) a defect of all memories ensues; ( 2 ) the magnitude of the memory-defect for different situations is greater for successively later-acquired memories of those situations; ( 3 ) the magnitude of the memory-defect of any one situation is greater for those of its significances and relations which the person has acquired in successively later periods of his l i f e ; ( 4 ) the larger the injury, the greater is this Icind of memory-defect. In agreement with the foregoing, we find that the defect in the memory for the names of objects and situations is less than in the ability to form sentences and propositions; that the memory for monosyllabic words is better than for polysyllables; that the memory of simple situations is better than that of complex situations. Interjections being primitive expressions, the memory for them is injured least ( 1 ) . Since the memory-defect of the kind outlined is in direct proportion to the extent of the injury of the association systems, we may safely assume that the reason why no memory-defect seems to result from very small injuries is that the defect is not sufficiently pronounced to be detected by the clinical methods at our disposal. An example of the different significances of a lead pencil during the successive periods of infancy, childhood, adolescence, and adult life, was given above. I have observed a right-handed man who had sustained a hemorrhage in the left hemisphere of the cerebrum and who largely recovered

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the use of his right limbs and of his speech. When, during the first stages of recovery, this patient was given a lead pencil, he grasped it and put it into his mouth. This is the significance of a lead pencil to an infant. Some days later he was given the lead pencil and some paper and by means of appropriate gestures 1 (he did not understand speech) was asked to write. H e grasped the lead pencil with his whole left hand and moved with it across the paper with such force that he tore it. A few days later still, I drew lines with the pencil on paper, before the patient, whom I then requested, by means of signs, to do the same. 2 The invalid again grasped the pencil in his left fist and placed the point against the paper, but failed to draw a line, crumpling up the paper by the movement instead. Somewhat later in the course of recovery, he was able to copy lines, very imperfectly at first, then with tolerable accuracy. This is the significance of a lead pencil to a young child. Later still the patient was able to copy more or less successfully, then to write. At the same time, his comprehension of vocal speech and his utterance improved. But he substituted words so badly, especially when fatigued or embarrassed, that his requests at times could not be understood, and on such occasions he exhibited much irritation. His capacity for naming objects improved rapidly. During this process he frequently transposed syllables or substituted wrong syllables, of which errors he became aware before he was able to correct them. For example, I once showed him an inkwell and asked him to name it. H e complied in the following manner: "Wilkin—no; welkin—no; wellking—no; wait—welling—wellink—inkw e l l ! " His syntax was very defective at this stage, with many transpositions and substitutions. It improved -very slowly. Months after he left the hospital, his sentence formation still exhibited occasional faults. The different forms assumed by this memory-defect are very numerous and an attempt to classify them would lead us far afield. Those interested may peruse the thorough works on the subject by Broca (2, 3, 4, 5, 6, 7, 8), Head ( 9 ) , Goldstein ( 1 0 , 1 1 , 1 2 , 1 3 ) , Weisenburg and McBride ( 1 4 ) , and the many other investigators to whom these authors refer. Suffice it to note in this place the two extreme types of aphasia. One exhibits a pronounced memory-defect in the sphere of the highly skilled movements which are involved in the expression of thought. The afflicted person understands what is said to him and can read; he recognizes his acquaintances and knows the uses and the significances of objects and conditions; but he can 1 Mimesis being a very primitive trait, it is to a certain extent preserved in these conditions. See Chapter X I I , " T h e State of A t t e n t i o n , " sections on imitation. 2 Intermediary stimuli. See Chapter X I I , " T h e State of A t t e n t i o n , " sections on imitation.

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neither speak nor write. In the other type the person has not only forgotten the movements involved in the expression of thought, but the meaning— the significance of objects and conditions—as well. H e can neither speak nor write; he does not recognize his friends and relatives; shown a previously familiar object, such as a lead pencil or a watch, he does not know what it is. T h e following considerations may offer a possible clue to the grosser differences in the memory-defects produced by lesions in different parts of the cerebral cortex. ANATOMICAL FACTS

T h e memory of a situation implies the memory of a number of sensations and feelings organized in certain ways. A nerve connecting directly the receptive area of smell with that of vision, let us say, could not subserve the memory of an entire situation, because there is no situation, no matter how simple, which might be conceived in visual and olfactory terms only. If the situation has dimensions, the conception partakes of muscle sense. If it has consistency, the conception partakes of the sense of touch; and so forth. T h e memory of a concrete situation must therefore reside in nerve systems interconnecting directly or indirectly all the sensory receptive areas of the cerebral cortex. As a matter of fact, the bulk of the cerebrum consists of just such nerve systems. Adjoining parts of the cerebral cortex are interconnected by relatively short nerves, and distant parts by longer nerves. In my own investigations I could not discover nerves which were long enough to extend the entire length of the cerebrum in any of its diameters. The nerve bundles which appear to extend for very long distances in the cerebrum may be likened to long strings, the constituent fibers of which are relatively short. Of these long bundles, three stand out prominently. One, which owing to its curved course is known as the arcuate nerve system, connects every part of the temporal, and a portion of the occipital and the parietal areas of the cortex, some of its fibers reaching into the rear portion of the frontal lobe (fig. 5 f ) . This nerve system therefore establishes connections between all the sensory receptive areas. T h e second nerve system is known as the uncinate (fig. 5G), from the hooklike appearance of its anterior portion. The connections which it establishes are far more extensive than might appear from a superficial view. It connects the temporal and temporosphenoidal regions with the entire prefrontal and frontal areas. T h e more posteriorly placed fibers of this bundle are successively less curved, so that those which extend between the middle

A

Central fissure

Temporal lobe

LATERAL SURFACE OF CEREBRUM

A

Central fissure

MESIAL SURFACE OF CEREBRUM Fig. 5. A DIAGRAM OF T H E A R R A N G E M E N T OF T H E "LONG" ASSOCIAT I O N SYSTEMS A N D O F T H E RECEPTIVE AREAS OF T H E HUMAN CEREBRUM A. Motor area. B. Somatic sensory area. C. Visual area. D. Auditory area. E. Smell (taste?). F. Arcuate system. G. Uncinate system. H. Inferior longitudinal system.

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of the temporal and the frontal lobes are straight, their directions being diagonally forward and upward. This fiber system therefore appears to establish connections between the sensory areas in the temporal and the temporosphenoidal regions and the prefrontal and frontal areas, including the motor area and probably the somatic sensory receptive area of the anterior part of the parietal region. The third "long" association system extends between the occipital lobe in the neighborhood of the calcarine fissure and the tip of the temporal, the prefrontal, and the anterior frontal areas. Owing to its length and its position, it is known as the inferior longitudinal fasciculus (fig. 5 h ) . Its constituent fibers originate or end throughout the length of the bundle in the regions mentioned, interlacing with the other two fiber systems. As far as I could ascertain, this nerve system interconnects the sensory areas of the occipital and temporal lobes and the prefrontal and anterior portions of the frontal lobe. From the anatomical arrangement of these connections, we may infer with reason that an injury, say of the size of a hazelnut, in the middle of the parietal area (of the left hemisphere in a right-handed person or of the right hemisphere in a left-handed person) must result in some degree of disorganization of memories of sensations and to a less extent in a defect of the relations between sensation and movement. Since the arcuate nerve system is in this region of the cortex spread out over a large area, a relatively small number of its fibers would be involved in the injury. But an injury of the same size in the region of the supramarginal and angular convolutions, where the arcuate system is gathered into a compact bundle, may sever a large part of it. In that case the memories of sensations would be almost completely disorganized and the aphasia, mainly of a sensory nature, would be profound. And this is in agreement with the clinical and the pathological findings that a lesion in the region of the supramarginal and angular convolutions is productive of a profound aphasia. On the other hand, an injury of the lower parts of the frontal convolutions, which border on the orbital area, must destroy a portion of the uncinate and the inferior longitudinal nerve systems, severing the receptive areas of smell, taste, hearing, and vision from the motor area. Since the lower part of the motor area contains the centers for the movements of the hands, the larynx, and the musculature of the face, such an injury must result in a disorganization of memories of sensations as they are related to the skilled movements of expression. Such aphasia is known as motor aphasia.

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T H E U L T I M A T E SEAT OF M E M O R Y

Whether, in the loss and disorganization of memory caused by injuries of the association systems of the cerebrum, the sensory constituents predominate in any one case, or whether the relation of sensation to movement is an outstanding symptom, the portion of the memory lost is in agreement with Hughlings Jackson's Law of Evolution and Dissolution of the Nervous System. Not all of the significances of any object, condition, or situation are lost to memory, while the relatively more complex and successively later acquired significances of every object, condition, and situation are lost. Since the magnitude of this loss is in direct proportion to the number of association nerves severed by an injury, we are impelled to the conclusion that, with the exception of the differences pointed out in the foregoing, all memories reside in every part of the association systems. A further pursuit of the logic revealed by the facts of the aphasias leads to the conclusion which the philosopher, according to his temper, will consider as being either entirely preposterous or profoundly significant—that every tenuous nerve of the hundreds or thousands of millions of association nerves contains a minute trace of all the memories of our experiences, and that the manifestations of memory are brought about by a multiplication of effects. D I S I N T E G R A T I O N OF C O M P L E X M E M O R I E S

Such are the conclusions regarding memory which may be drawn from the disturbances of language known as the aphasias. Other disorders make for a degree of modification of these conclusions. Diseases of the prefrontal regions of the cerebrum are not especially marked by disturbances of language. The loss of memory in these diseases is of a different kind. There is a disintegration of that most complex organization of experiences which manifests itself in the character or personality of the individual. There is a loss of the higher phases of reason and judgment, the personality sinks to a low level, frequently expressing itself in shallow witticism, in practical jokes, in senseless obscenity, in a lack of care for the future, in total disregard for the interests of others (15, 16). SUMMARY

1. Each of the different categories of sensation contains a large number of classes, and each such class a large number of units of different strengths and shades, thus making for a vast variety of states of consciousness. These

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are further multiplied by the difference in the effect produced by any one stimulus under different external and internal conditions. 2. The association systems of the cerebral cortex are the repositories of memory (in the ordinary meaning of the word). 3. Although the different forms of aphasia may be largely explained by the particular location of the causative injury, the fact remains that on the whole the magnitude of the memory-defect is in direct proportion to the extent of the injury. 4. In the course of aphasia, the successively earlier acquired and simplest, that is, least complex, memories are least involved and are the first to recover. The successively later acquired and most complex memories are most profoundly involved and are the last to recover. In this respect, therefore, the memory-defect is subject to Hughlings Jackson's Law of Evolution and Dissolution of the Nervous System. 5. A pursuance of the logic of facts gathered from the aphasias leads to the conclusion—either absurd or most significant—that all memories are contained in each of the nerve fibers of the association systems. 6. Diseases of the prefrontal regions of the cerebrum are productive of disintegration of the most highly integrated memories, such as are manifested in the acts of reasoning and judgment. REFERENCES 1 . Jackson, J . Hughlings. " O n Affections of Speech from Disease of the Brain." Brainy

I I ( 1 8 7 9 - 8 0 ) , 203.

2. Broca, P . "Perte de la parole. Ramollissement chronique et destruction partielle du lobe antérieur gauche du cerveau." Bull.

d. I. Soc. d'AnthropII

( 1861 ), 235.

3 . Broca, P . "Remarques sur le siège de la faculté du langage articulé, suivies d'une observation d'aphémie." Bull.

d. I. Soc. Anatorn.,

V I ( 1 8 6 1 ) , 330.

4 . Broca, P . "Nouvelle observation d'aphémie produite par une lésion de la moitié postérieure des deuxième et troisième circonvolutions frontales." Bull. Anatom.y

VI (1861),

d. I.

Soc.

398.

5 . Broca, P . " D e u x cas d'aphémie traumatique, produite par des lésions de la troisième circonvolution frontale gauche. Diagnostic chirurgical." Bull. Chirurg.,

d. I. Soc.

d.

V (1864), 51.

6. Broca, P. " S u r l'aphémie." Bull.

d. I. Soc. Anatom.,

7. Broca, P. " S u r la faculté du langage articulé." Bull.

I X ( 1 8 6 4 ) , 296. d. I. Soc.

d'Anthrop.,

VI

( 1 8 6 5 ) , 4938. Broca, P. " S u r le siège de la faculté du langage articulé." Trib.

méd.,

( a ) No. 7 4

( 2 8 fév. 1 8 6 9 ) , pp. 2 5 4 - 5 6 ; ( b ) N o . 7 5 ( 7 mars), pp. 2 6 5 - 6 9 . 9. Head, Henry. Aphasia and Kindred Disorders of Speech. 2 vols., N e w T h e Macmillan C o . , 1 9 2 6 .

York,

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0. Goldstein, K . "Das Wesen der amnestischen Aphasie." Schweiz. Arch. f . Neur. u. PsychiatXV ( 1 9 3 4 ) , 163. 1. Goldstein, K . "Über Aphasie." Schwerz.. Arch. /. Neur. u. Psychiat., X I X ( 1 9 2 6 ) , 3. 2. Goldstein, K . "Die zwei Formen der Störungsmöglichkeit der Sprache durch Hirnschädigung." Arch. f . Psychiat. u. Neruenhk., X C V ( 1 9 3 1 ), 730. 3. Goldstein, K. "L'Analyse de l'aphasie et l'étude de l'essence du langage." J. de pychol., XXX ( 1 9 3 3 ) , 43°4. Weisenburg, Theodore, and Katharine E . McBride. Aphasia. New York, T h e Commonwealth Fund, 1 9 3 5 . 5. Baruk, Henri. Les Troubles mentaux dans les tumeurs cérébrales. Etude clinique, pathogénie, traitement. Paris, O. Doin, 1926. 6. Brickner, Richard M. The Intellectual Functions of the Frontal Lobes. A Study Based upon Observation of a Man after Partial Bilateral Frontal Lobectomy. New York, The Macmillan Co., 1936.

CHAPTER

EIGHT

REPRESENTATION AND SYMBOLISM T H E BIOLOGICAL CAUSES OF R E P R E S E N T A T I O N AND SYMBOLISM

For an understanding of the mental operations we must acquaint ourselves with the image of the outer world, formed in the inner world of memory. The earth contains a practically infinite variety of things, and an endlesfe variety of conditions prevail upon it. The animal must avoid coming in contact with a certain number of these and it must select others to be appropriated by it. Since every object or condition is possessed of a practically infinite number of attributes, different objects or conditions are consequently possessed of a number of the same attributes. Discrimination is therefore frequently difficult. The appearance and taste of certain poisonous mushrooms are much like those of the edible varieties; a quagmire may be easily mistaken for firm ground; milk contaminated with germs of disease has, to the unaided senses, the same appearance, the same odor and taste as pure milk, and so forth without end. To a certain extent this difficulty is overcome by the animal armed with different appliances for discriminating and choosing. For example, in the task of discriminating between two objects which are in every respect the same except for a difference in weight, the receptor organs of muscle sense are so affected by this difference that the animal must oppose to each of them a different degree of muscular tension in order to balance a given pull or push on the muscle. Of a hundred and more human beings and animals who may have traversed the same road, the dog, by means of the olfactory receptors, is able to determine whether his master was among them or not. It must be borne in mind in this connection that the value of any sensation is relative to the amount of past experience with that and with other sensations. In other words, the significance to the organism of any object or condition depends on the manner in which and the degree to which present

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impressions are modified by previous experiences with similar and dissimilar impressions. In terms of nerve physiology, the reaction of the organism to any situation very largely depends on the kind and degree of modification undergone by present nerve impulses from the sensory receptors in their passage along the nerve pathways of the cerebral cortex, the latter having been themselves modified by the previous passage along them of nerve impulses. Without going deeply into the matter, it may be stated that the basis of this process is to be found in the feature of nerve conduction along the cerebral reflex arc, which is distinguished from conduction in a nerve trunk by the fact that the effectiveness of a stimulus applied to the former depends not only on that stimulus but largely on the stimuli which have preceded it ( i ) . 1 The recognition of an object or condition is therefore achieved by an appraisal of its several attributes and of their relations to one another, by correlating the impressions produced by them on the different sense organs with memories of similar impressions and of the reactions to such impressions. We decide, for instance, that a certain object is an apple because of the particular impressions it makes severally on our visual, tactile, gustatory, olfactory, and other sense organs, and the relation in which these impressions stand to our past experiences with apples as distinguished from other objects. It goes without saying that the more of our sense organs that are brought to bear upon the examination of the apple and the more detailed the correlation of such impressions to past experiences, the more appropriate is apt to be the consequent reaction. In the case of the human being, moreover, an ever-increasing amount of past experience is brought to bear upon such an examination. The microscope, the telescope, the radio, the telephone, chemical analysis, and the numberless other appliances for making accessible to the sensory receptors attributes of objects and conditions which would not be accessible to them otherwise, are the embodiments of accumulated past experiences integrated and organized in certain ways. It will appear, however, that an accurate conception of an object or condition by the appraisal of a large number of its attributes necessitates a cor~ responding length of time. And notwithstanding the fact that a more accurate adjustment of the consequent reaction must be the result, the time factor 1

" W h a t we desire to stress in regard to the reaction of the cortical point on the antagonistic muscle-pair is the influence of shortly pre-current excitations, both of itself and of other points, and of efferent channels." Brown and Sherrington.

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involved must operate in the long run disadvantageously. T h e postponement of a reaction to such ordinary objects as a loaf of bread or a venomous snake until a large number of the attributes of these objects has been ascertained, might result in the death of the person long before he is done with the examination. As a matter of fact, the reactions of animals to the situations in their surroundings take place without a thorough examination of their attributes. Such reactions are not always the most advantageous ones, but on the whole those animals will survive who can respond within the limited time at their disposal j and in most instances in which the life of the animal is at stake that time is brief. Therefore, although an animal may have acquired experiences with a large number of attributes of a given object or condition, it reacts to it after examining only a very few of these. Such a mode of response is true of all animals, from the lowest to the highest. T h e very fact that an amoeba will occasionally engulf a poisonous particle and die, is proof that the reaction was to certain of its attributes which did not adequately represent the entire aggregate. Jennings ( 2 ) brought to bear a large amount of observation on the importance of response of the lowest animals to representative stimuli. T h e organism [says that author] may react to changes that in themselves neither favor nor interfere with the normal life activities, but which do lead to such favor or interference. . . . Thus, Stentor may bend toward a small solid body when touched by it, this reaction aiding it to procure food, though there is no indication that the touch is directly beneficial. Or it may contract away from a light touch, this enabling it to escape from a possible approaching enemy, though the touch itself is not injurious. . . . Euglena reacts negatively when its colorless anterior end alone is shaded, yet it is only when the shadow affects its chlorophyll bodies that it interferes with metabolism. The flat-worm may turn toward a weak stimulus of any sort. This leads in the long run to its obtaining food, though sometimes the stimulus does not come from a food body. . . . The sea urchin tends to remain in dark places, and light is apparently injurious to it. Yet it responds to a sudden shadow falling upon it by pointing its spines in the direction from which the shadow comes. This action is defensive, serving to protect it from enemies that in approaching may have cast a shadow. T h e reaction is produced by the shadow, but it rejers, in its biological value, to something behind the shadow. In all these cases the reaction to change cannot be considered due to any direct injurious or beneficial effect of the actual change itself. The actual change merely refresents a possible change behind it, which is injurious or beneficial. The

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organism reacts to something else than the change actually occurring} the change has the function of a sign. We may appropriately call stimuli of this sort representative stimuli. The truth of the proposition becomes the more obvious as we ascend in the animal scale. T h e effectiveness of the fly paper, of the fishhook, of the rat poison, and of the empty preelection promises alike testify to the fact that animals' reactions are not to the entire aggregate, but only to a small number of attributes of any object or condition which are determined to be representative of that aggregate. As all mental processes are based on the principle of response to representative attributes or to symbols of objects and conditions, an evaluation of the different degrees of representation is highly pertinent to the subject with which we are dealing. As a matter of fact, the phenomena of thought, imagery, and dreams or hallucinations cannot be understood without such an evaluation. D I R E C T REPRESENTATION

The most appropriate reaction possible to a situation is to its most direct representation by a certain number of its attributes. Since the number of attributes of any entity is practically unlimited, and since the response of the organism is at best directly to a number of these, it follows that, other things being equal, the degree of appropriateness of a reaction is in direct proportion to the number of attributes of the object or condition on which it is based and to the degree to which these are characteristic of it—the degree of constancy of their presence in the particular situation or entity and that of their absence from all others. Thus the shape, size, color, and weight of an apple may be simulated with relative ease by other objects, say by an artificial apple, but the taste of an apple is characteristic} and if that attribute, in addition to the others mentioned, is taken as representing all of its attributes, the subsequent response is likely to be the more appropriate. H o w difficult it is to fulfill the foregoing requiremeots of number and inalienability of representative attributes of an entity is evidenced by the difficulties encountered in such a task as that of classification. T h e Encyclopaedia Britannica defines classification as "a logical process common to all special sciences and to knowledge in general, consisting in the collection, under a common name, of a number of objects which are alike in one or more respects." T h e extent to which the same attributes of a number of different objects or conditions are sufficiently representative to justify the

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placing of that number under a single heading is, however, so uncertain that throughout the ages, and to the present day, scientists have found it difficult to agree completely on any one classification. And this is true even of the physical sciences, which have been classed differently by every scientist or philosopher who has ever undertaken that task. T h e case could indeed hardly be otherwise. The progress of knowledge implies the discovery of an ever-increasing number of attributes of objects and conditions, as well as an increasingly accurate determination of their relations to one another. The classification of objects and conditions into groups, on the basis of like representative attributes, must therefore continually change. INDIRECT

REPRESENTATION

T h e chances of an erroneous response to a situation become greater when this rests on the basis of representation of its attributes by another person— on the basis of re-representation. Of a number of causes for such a state of affairs, one is the fact that the significance to a person of any object or condition is derived from his particular past experiences with it. And as the past experiences of different persons are different, so are the significances of any one object or condition different to different persons. F o r example, the person whose past experience with apples is to the effect that they made him ill, may represent them to a child as poisonous fruit, and if such representation is effective in calling forth a corresponding reaction, the latter must be erroneous. T H E P A R T OF R E P R E S E N T A T I O N IN E D U C A T I O N

In any system of education the importance of the principle of representation cannot be overestimated. Great as are the benefits derivable from the proper use of this principle in the conservation of time and energy, they are to a large extent counterbalanced by the harm which results from its abuse. As even the most direct representation is liable to error, such liability increases with every step in the process of re-representation. T h e parent, the nurse, the teacher, the book, are the sources of the child's information, the representatives of the truth. But as these representatives are frequently removed by many steps from the original representatives of the truth, it is often the case that the child's informers really represent falsehood. As there can be no first-hand information regarding the history of preceding generations of men, of animals, and of plants, or of the changes undergone in the past by the earth, such knowledge is at best gained only by processes of

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inference and deduction. Inasmuch as the result of deduction depends to a great extent on the past experiences of the deducer, it varies with the variation in the past experiences of different persons. The processes of inference and deduction are therefore subject to error; and whatever the extent of the original error, it is multiplied by repeated representation and re-representation. It is to such a process that the history of the supernatural largely owes its existence. REPRESENTATION IN G O V E R N M E N T

Although the errors involved in the principle of social representation are in great part familiar, it might be worth while to point them out briefly in this place. In order to save the time and the energy involved in the mutual adjustment of the various civic and economic interests of a large number of persons, this task is delegated to representatives. The latter, in their turn, appoint a large number of persons entrusted with the execution of the governmental tasks. The subordinate official, or the soldier, who represents his superior, who in his turn represents a higher official, and so on in the many steps of the hierarchy of officialdom, is so far removed from the original interests which he is alleged to represent, that it is only by dint of excessive vigilance on the part of the persons represented that the system does not degenerate into a tyrannical bureaucracy on the one hand and into a despotic autocracy on the other. The necessity imposed on governments of supplementing the services of the several departments by the work of spies and eavesdroppers is proof of the fact that social representation is subject to the same faults to which representation in general is subject. REPRESENTATION IN A R T

A painting of a landscape represents the scene on a two-dimensional plane, by means of certain lights, shadows, and colors, in correspondence with the past experiences of the painter. Inasmuch as a photograph of the painting eliminates the colors and represents them by lights and shadows, it is no longer a representation of the landscape but of the painting. Should another painter attempt to reproduce the photograph in color, he will introduce his own past experiences with the colors, perspective, and movement. By a repetition of this process, the essential features of the original landscape may be changed beyond recognition. If this ultimate product bears the legend of the original painting—"Siberian Tundra," for instance—the mental reactions, based on the representation, of a person to a real Siberian tundra must be inappropriate.

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EFFECTS

T h e work of numerous investigators on the physiology and psychology of the emotions, from Bell ( 3 ) and Darwin ( 4 ) to James and Lange ( 5 ) and Cannon ( 6 ) , testifies to the fact that a sensory impression, or a thought, initiates a widespread disturbance throughout the body, which corresponds in certain ways to the external disturbance which was productive of the sensation. T h e mental index of such an internal disturbance is the feeling of an emotion. That the internal disturbance leaves in its wake more or less permanent changes, is attested by the fact of memory. And the latter is true not only of animals possessed of a cerebrum, but to a certain extent of those lowest in the scale as well. T h e observation of more or less lasting changes in the behavior of the lowest animals as a result of impressions received, points to tissue changes resulting from impressions imparted to the body by external disturbances which correspond to the latter in certain ways. Amoebas react negatively to tap-water [says Jennings ( 2 ) ] , or to water from a foreign culture, but after transference to such water they behave normally. . . . When white light is thrown on an Amoeba it ceases to move, but if this light continues, the animal resumes movement. T o constant conditions Amoeba tends to become acclimatized. In sea anemones a light stimulus that is not injurious may cause at first a marked reaction, then, on repetition produce no reaction at all or a very slight one. Thus, a drop of water is allowed to fall from a height of 30 cm. on the surface of the water just above the outspread disk of Ai-ptasia annulata. T h e animal at once contracts completely. After the animal has expanded, another drop is allowed to fall in the same way. As a rule there is no response to this or to succeeding drops. Perhaps the lowest animal in which the enduring modification of behavior has been demonstrated is the flatworm Convoluta roscoffensis. . . . As the water rises, and the waves begin to beat on the sand near them, they go downward into the sand, where they are protected. As the water sinks, the animals creep upward and appear again on the surface. . . . If the worms are removed to an aquarium . . . they continue to go downward at the period of high tide, upward at the period of low tide . . . for about two weeks, so that the worms may be . . . used for a time as tide indicators. But under such conditions the periodicity after a time disappears, showing that it was really due to the external factor—the tides. . . . T h e present action of Amoeba, even when responding to stimuli, depends, as a result o f . . . temporary differentiations, partly on its past action. . . .

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Since under the same external conditions the action changes, the animal itself must have changed, otherwise it could not now behave differently from before. The child or the susceptible adult in whom such relatively permanent tissue changes have been brought about by the auditory and visual sensations of listening to or reading certain representations, must have the behavior adjusted in a corresponding way. If these representations have been false, as is the case in stories of miraculous cures achieved by the utterance of certain words j of the activity of floods and earthquakes arrested by charms and incantations; or in any of the ways in which ignorance misrepresents relations of cause and effect; then the behavior formed on the basis of such representations is adjusted to nonexistences, and is inappropriate amidst the reality of the surroundings. Nor will subsequent reeducation erase completely the false record wrought in the tissues of the body. This fact is familiar to clinicians who have observed the reversion of educated adults to the mental and physical behavior of childhood, in conditions which are depressing to the nervous system. SYMBOLISM

Direct representation contains a certain number of attributes of the object or condition represented. In the course of a number of re-representations, those attributes may often no longer be recognized, the representation having become a symbol which stands for the given object or condition. There is, therefore, no definite line of demarcation between a representation and a symbol; a representation which is sufficiently remote is largely a symbol. SYMBOLISM A M E A N S FOR R E S P O N D I N G TO A C O M P L E X S I T U A T I O N AS A WHOLE

Mention was made of the importance to the animal of responding to a few representative attributes of a situation, rather than to many, as a means of conserving energy and time. It remains to be added here that the smaller the number of representative attributes to which the animal responds, the more abbreviated is the consequent reaction and the greater still is the conservation of its energy and time. A symbol, being the most abbreviated form of representation, is therefore capable of covering a wide range of significance, and is for that reason a dominant factor in the life of animals, especially the higher animals. It is by means of symbolism that an animal is enabled to respond by a single reaction to an entire situation, instead of by separate reactions to each of its details. T h e problem of why and how the

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animal responds to a situation as a whole is thus simply solved by the key of the symbol. T H E S Y M B O L A M E A N S OF CONSERVING E N E R G Y AND T I M E

The conservation of the animal's energy and time by such a mode of response is greater than appears at first sight. Examples of the fact that the more extensive the significance of a given symbol, the greater the conservation of time and energy on the part of the animal, are numerous and familiar. Consider the significance to the informed person of the symbol of the label on the milk bottle. To such a person the label tells a long and complicated story regarding the contents of the bottle—the quantities of fat, protein, water, milk sugar, salts, and vitamins which it contains; the probable degree of absence of bacteria of disease; the manner in which the cows have been fed, protected, and handled; the condition of the barns; the cleanliness of the clothes and the hands of the attendants; the processes of pasteurization, homogenation, examination, transportation, bottling, and distribution; and so forth. Having acquired from past experience the extent of the significance of the symbol of the label on the bottle, the informed person is enabled to respond to all of the attributes of the milk by a single appropriate reaction, positive or negative, as the case may be. On the contrary, a person not so informed may do one of two things. H e may either drink the milk from a bottle which is not marked by a symbol and thus run the risk of contracting disease, or, if he stands informed of the possibility of contracting disease from drinking impure milk, he must proceed to examine it anew every time before drinking or discarding it. T H E E V O L U T I O N OF R E P R E S E N T A T I O N INTO SYMBOLISM

Since the reduction in the number of representative attributes of a situation enables the animal to respond to it as a whole, and since a symbol contains the minimum number of such attributes, we are prepared to assume that the general course of the evolution of representation is in the direction of symbolism. A review of the course of the evolution of different phases of representation corroborates such an assumption. SYMBOLISM IN W R I T I N G

The evolution of writing is from representation to symbolism. The writing of primitive peoples consists of pictures which embody the outstanding features of the situation which they wished to represent. I am informed that

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the ancient written Chinese word for "domestic harmony" is a picture representing a roof with a man, a woman, and a boy beneath it j that the written word for "domestic difficulty" is a picture representing two women and a man under the same roof; that the written word for "gossip" is a representation of three women sitting together. In the course of time the ancient complicated representations became so simplified that at present they no longer contain any of the features of these several situations, and the drawings are merely symbolic of them. A picture of an object was, in the ancient Egyptian writing, the word for that object. Thus the word for a person's head was the picture of a head. Abstract entities, such as prevailing conditions, or states of being, were represented by pictures of concrete objects whose salient features were usually concomitant with the prevailing conditions or were associated with the states of being which the writer meant to convey. Thus the word "wind" was represented by an inflated sail; the word "to rule" was indicated by the picture of a scepter; the word "clean," by water pouring from an inclined vase (fig. 6).

A sceptei— to rule An inflated sail - wind

Weiter coming from 01 vase clean

Fig. 6. THE REPRESENTATION OF CONDITIONS OR OF ABSTRACT ENTITIES BY CONCRETE OBJECTS

In the course of time, however, a more concise mode of conveying to the eye sounds of articulated words was arrived at by representing each separate syllable by the picture of a different object. At a still later period such pictures were made to represent separate letters, the first letter of the name of a pictured object standing for the letter in the written word, in the manner in which we sometimes accentuate the sound of a letter to a listener on the telephone by saying " J for John." At the same time, by dint of simplification and abbreviation, the pictures were progressively losing their character as representations, thus becoming more and more symbolic.

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W e have all seen the alphabet illustrated by pictures in primers and first readers [says Ilin ( 7 ) ] . W e all learned to read in books with pictures where there was a picture of an Axe beside A , of a Bee beside B, and so on. . . . But none of us ever thought of representing the syllable A B by a picture of an Axe and a picture of a Bee. But that's just what the Hyscos did. For the sound A they began to draw the picture of an ox's head, because in their language the word for ox was Alef>h. For B — a house, which in their language was Bet. For R — a man's head, which in their language was Resh. So they got a collection of twenty-one letters. T h e evolution of these representations into the modern symbols is shown by the following somewhat diagrammatic illustration (fig. 7 ) .

M

Ox

House

en

Corner Man shouting "hey!" Palm branch Water

qj

A a

Ô

r L

1 ^

y

Atww

A

1

1 A

ï

/ -v

à B & E3 r r G G e L K. k K M

41 9 Egyptian

A 4 Phoenician

Hyskos

Old Greek

(Atepht (Bet)

(A M

v\ N N

Snake

P- 138]. The action of cannabis indica: Soon after its administration, the patient passes into a dreamy, semi-conscious state, in which the judgment seems to be lost, while the imagination is untrammeled by its usual restraints. The dreams assume the vividness of visions, are of boundless extravagance, and, of course, vary with the character and pursuits of the individual. . . . Ideas flash through the mind without apparent continuity, and all measurement of time and space is lost. True hallucinations may appear. . . . The sensation of pain is lessened or entirely absent, and the sense of touch is less acute than normally. Later the dreams alternate with periods of complete unconsciousness, from which the patient can be aroused easily, and the symptoms eventually pass into tranquil sleep [78, pp. 263, 264]. The action of bromides: Bromides are powerful depressants to the nervous system; (the action of the potassium salt being most marked). Thus, if an animal be given large doses of any of them, irritation of the cortical motor areas, which before easily excited movements, fails to do so. Experiments also show that the reflex excitability of the cord is considerably diminished, and that the activity of the sensory mechanism is also impaired, for large doses of bromides given to frogs cause cutaneous anaesthesia. In man, at least, not only the cortical motor area, but the brain as a

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whole is depressed, therefore these drugs are powerful hypnotics. It is probable that in addition to the brain and spinal cord the peripheral nerves are depressed, so that bromides are well worthy to be called powerful nervous depressants. The activity of the muscles is also diminished, not only by the action of the drugs on the nervous system, but by their direct action on them [76, pp. 238, 239]. . . . Their specific action on the central nervous system . . . begins with depression of the psychological functions, the motor area and the medulla and cord, the last being shown by the diminished reflexes. The depression does not show an evolutionary progress as after alcohol. There is none of the uproariousness of the drunkard—the outcome of an overactivity of lower centers which have not yet succumbed to the poison—but on the contrary, all the cells, psychological, motor area, medulla, and cord are affected at the same time [77, p. 401]. The bromides tend to produce a mental calm . . . progressing to sluggishness, lack of attention and lassitude. These all dispose toward sleep [75, p. 878]. The action of these compounds may be summarized in the statement that they are general depressants of the nervous system. Perhaps their tendency to reduce motor functions is secondary to sensory depression, with consequent diminished reflexes, but it appears that in part, at least, the motor areas are directly affected [74, p. 428]. On the whole of the nervous system, except the medulla, there is moderate but lasting general depression [79, p. 420]. The chief phenomena are reduction of reflexes and diminution of acuteness of perception [80, p. 1716]. The action of barbital compounds: The action is limited almost, if not entirely, to the brain and cord. . . . The motor cells of the cord are more depressed than the sensory and reflexes are lost before pain sense [80, p. 1619]. The usual dose induces a deep, dreamless sleep [75, p. 757]. S U M M A R Y OF T H E FACTORS I N V O L V E D IN S L E E P

In the course of evolution those organisms have survived which could concentrate their activity for the acquisition of a stock of energy from the surroundings during the periods when prevailing conditions were favorable, and which ceased activity when conditions in the surroundings were unfavorable for such acquisition. Certain unicellular organisms, which live in shallow pools, are active as long as they are in water. When the pool in which they live dries up, these organisms become dry, active life ceases, and

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they float in the air, carried by air currents with the dust. If they happen to drop into a pool, living activity begins anew. During the cold season, when food is not obtainable or is obtainable only with difficulty, a number of animals hibernate. Most seeing animals cease their activity in the dark. With the cessation of muscular activity, the internal organs are not called upon to furnish energy-producing substances beyond the amount which is necessary to maintain the tissues alive. The processes of oxidation, secretion, excretion, and circulation are therefore at a low ebb, while the passage of elaborated nutritive substances and of water from the gastrointestinal tract into the blood continues. The molecular dislocation and deformation of the tissues resulting from a period of activity cease when the organism is at rest, and the tissues resume their normal form and relations. The several bodily storehouses of energy-producing substances, exhausted by a period of muscular activity, are replenished during rest. Elaborated nutritive substances continue to accumulate, to the point where their excess is sufficient to overcome the inertia of relative immobility, when muscular activity recommences, coinciding in point of time with the conditions in the surroundings which are favorable for such activity. Organs and functions are evolved in correspondence with the conditions imposed on the organism by its surroundings. One of the conditions being a restriction of organic activity to rather regularly intermittent periods of time, organs and functions have been evolved for the regulation of those periods of activity. The function of sleep, being a metabolic function, is largely under the control of the highest nerve structures which regulate the vegetative functions—the thalamus and hypothalamus. The most obvious manifestations of sleep are unconsciousness and muscular flaccidity. The former implies a disorientation of the organism both in the present and in the past. The processes of falling asleep and of awakening furnish a clue to some of the conditions which underlie the mental activities of thought, imagery, and hallucination. Insofar as these three modes of operation of the mental functions consist of a subjective reproduction of actual—objective—experiences, they constitute essentially an orientation in the past, in contrast to the activity of the receptive portions of the nervous system, which, by keeping the organism "in touch" with its sourroundings, orients it in the present.

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T h e diminution of sensory reception in the onset of sleep sets going the activity of the associative apparatus of the cerebral cortex. This activity consists of an orientation in the past, manifested in the functions of thought, imagery, and hallucination. Thought, imagery, and hallucination differ from one another in the following ways. In the order mentioned they contain diminishing amounts of orientation in the present, are increasingly inaccurate, and increasingly vivid. With the progressive diminution of sensory reception, that activity of the cerebral cortex which consists in relationing, is diminished, and its control of the autonomic emotional functions of the thalamus and hypothalamus becomes in consequence correspondingly weaker. T h e functions of the latter therefore dominate the subjective experiences to a corresponding extent. In other words, to the extent that the cortical function of correlating the parts of a subjective experience becomes defective, the emotional factor of vividness of the separate parts of this experience is increased. In thought, the separate parts of the memory of a situation are relatively vague, yet their mutual relations are accurate. In imagery and especially in hallucination, on the other hand, those parts are vivid, yet their mutual relations are inaccurate. As may be inferred from the persistence of mental activity when sensory reception is largely extinguished, the process of dissolution of the nervous functions in the onset of sleep does not affect equally the entire nervous system at the same time. The progress of suspension of nerve function in sleep proceeds, rather, in the anatomical course of the cerebral nerve pathways, in the normal direction of nerve conduction. Beginning in the receptive fields, it next involves the intercalated nerve structures of the cerebral cortex—the association systems—and next to that the efferent, or motor, systems. In other words, the functions of the afferent, the associative, and the efferent portions of the nervous system are, in the order mentioned, successively extinguished. T o the extent to which the receptive portion of the nervous system is disabled, the next succeeding links of the nerve pathways—the association apparatus of the cerebral cortex—are activated. T o the extent to which the associative apparatus is then in its turn disabled, the third portion—the motor and thalamic—is activated. In the progress of functional extinction of the nerve pathway from the receptive toward the motor portions, the course of normal sleep is manifested by the following subjective and objective phenomena:

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1 . The sensory receptive apparatus is partially deprived of stimulation by the prone posture, by the exclusion of light, of sound, and other external disturbances. The result of such partial deprivation of sensory reception is a diminished orientation in the relatively immediate surroundings and in the present time.7 To the extent to which the person is thus disorientated in the immediate present, the function of the association systems manifests itself by that orientation in the past which constitutes the function of thought. 2. The activity of the receptive portion of the nervous system is further diminished, with the consequence that the person becomes increasingly disoriented in the present. To the degree to which he becomes thus disoriented in the present, subjective reproduction of his past experiences, under insufficient guidance by the actualities of the surroundings, becomes more vivid and more inaccurate. This is the stage of imagery. 3. The function of the receptive portion of the nervous system is now largely in abeyance; the person is therefore largely anesthetic and disoriented in his present surroundings. In the absence of guidance by the surrounding actualities, that activity of the association systems which manifests itself in relationing, largely ceases, and cortical control of the thalamic emotional functions is thereby weakened, with the result that the subjective reproductions of past objective experiences become vivid in proportion as their relations become defective. This is the stage of hallucination. 4. The succeeding portion of the nerve pathway—the association systems of the cerebral cortex—next becoming completely disabled, the person is entirely disoriented both in the present and in the past, that is, he is unconscious. Concomitant with the disability of the association systems, the succeeding—the motor—portion of the cerebral nerve pathway becomes activated. This is manifested by turning, crouching, and stretching movements of the body and the limbs. 5. The efferent, or motor, systems of the cerebral cortex next become disabled. The person is, under these circumstances, to a certain extent functionally decerebrated. This is manifested by an increased tonicity of the muscles, by increased tendon reflexes, and frequently by sudden movements of extension—by jerking or startling movements—and in certain instances by ankle clonus and the dorsiflexion of the great toe on stimulation of the sole of the foot—by the sign of Babinski. 7

See p. 100, n.

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6. With the progress of extinction of the motor mechanisms, its lowest parts are next involved—the motor centers in the brain stem and in the spinal cord. The musculature then becomes flaccid and the tendon reflexes disappear. 7. The recovery of nervous function in the course of awakening is on the whole marked by the same stages as those which occur in the onset of sleep, except that these succeed each other in the reverse order. In other words, the return of function begins from the muscular end of the nerve pathway and proceeds toward the afferent, the receptive, portion. Of the number of reasons for the inaccuracy of the subjective reproduction of past experiences in imagery and dreams, the following are among the most important: 1. The activity of the association systems is initiated by a diminution of sensory reception. The chances of an equal rate of diminution of function in all parts of the receptive apparatus are infinitely small. And as the activity of the different functional units of the association systems is, in consequence, initiated at different times and to different degrees, the reproduction of any given experience must be a pattern in which a number of parts are missing. The reproduction is therefore a distortion of the original pattern. This defect, however, follows the Law of Dissolution. T h e successively later acquired parts of any whole experience drop out, leaving behind the earlier acquired parts. Thus in the instance given of the different significances of a lead pencil, acquired in successively later periods of life, a lead-pencil merchant might, for example, dream that he was selling lead pencils to people who grasped them and put them in their mouths. 2. Our knowledge of the relations of parts to a whole and of the relations of wholes to one another increases throughout life in the course of experience. A knowledge of relations necessarily comes after a knowledge of the things or conditions correlated. The greater number of even the most common relations is inferred or gained only by remote representation. Our knowledge of relations is therefore largely imperfect. 3. Representation and symbolism, of which all animals make use for the speedy recognition of objects and conditions, is subject to unavoidable error. The human being, who makes the most extensive use of representation and of symbolism in spoken and written language, who employs comparisons and other figures of speech for the purpose of conveying certain meanings, is therefore most subject to an erroneous mental reproduction of objective

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experiences, in those states in which likeness is confused with identity and in which illusion becomes delusion. 4. The fact that the distorted subjective reproduction of objective experiences in the imagery and hallucinations of sleep is remembered, is evidence of a more or less permanent change, of a certain kind, in the body. That this change, produced by dreams, is to a large extent effective in controlling future behavior in the same manner as that produced by actual objective experiences, is evidenced by a very great number of historical facts. T h e content of the imagery and the dreams of a person whose behavior is partly based on dreams must be a further distortion of actualities. From the point of view of the subject with which we are dealing, all hypnotic drugs are divisible into two classes. Disregarding their individual peculiarities, one class of drugs induces a kind of sleep in which the diminished function in preceding nerve links and the ensuing activation of function in the succeeding links of the nerve pathway proceed in the same order as in normal sleep. In the sleep induced by the other class of drugs a progressive diminution and final suspension of all cerebrospinal nerve functions are the only evident effects. The sleep which results from certain states of attention has been dealt with in connection with that subject. REFERENCES

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48. Guillain, G., I. Bertrand and Périsson. "Étude anatomo-clinique d'une tumeur du Illme. ventricule." Rev. neurol., XXXII (1925), tome I, 467. 49. Marinesco, G., St. Draganesco, O. Sager and A. Kreindler. "Recherches anatomo-cliniques sur la localisation de la (onction du sommeil." Rev. neurol., XXXVI, (1929), 481. 50. Högner, P. "Die klinische Erscheinungen bei Erkrankungen des 3. Gehirnventrikels und seiner Wandungen." Deutsch. Zeitschr. f . Nervenheilk., XCVII (1927), 238. 51. Kleist, K. "Schlafstörungen, Schlafsucht bei Herderkrankungen des Gehirns." Arch. f . Psychtat., L X X X V I (1928), 303. 52. Fulton, J . F., and Percival Bailey. "Contribution to the Study of Tumors in the Region of the Third Ventricle: Their Diagnosis and Relation to Pathological Sleep." Journ. Nerv, and Ment. Dis., LXIX (1929), I, 145, 261. 53. Hechst, Béla. "Anatomische Beiträge zur zentralen Regulation des Schlaf-Wachseins." Arch. f . Psychiat., LXXXVII (1929), 505. 54. Foerster, O., and O. Gagel. "Ein Fall von Ependymcyste des III. Ventrikels." Zeitschr. f . d. ges. Neur. u. Psychiat., CXLIX (1933), 312. 55. Rowe, S. N. "Localization of the Sleep Mechanism." Brain, LVIII (1935), 21.

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CONCLUDING REMARKS The function of science is to adjust the human being to ever-wider domains in his surroundings. Being the result of experience, science cannot go beyond it, and therefore does not undertake to give an ultimate answer to any question. Every improved method of investigation opens vistas into unknown regions which, when explored, reveal openings into wider regions, and so without end. This must be likewise true of the investigation just concluded. The explanation given of the mechanism of thought, imagery, and dreams is limited to the present scope of experiment and observation. The exploration of the new regions opened by this investigation to the educator, the psychiatrist, and the physician will necessitate the assistance of the chemist and the physicist, as will become clear from the following considerations. On the basis of the present investigation, the function of thought may be defined as a subjective reproduction of objective experiences, in which orientation in the past is co-existent with and guided by a large amount of orientation in the present; and which, notwithstanding the vagueness of the sensations re-experienced, is accurate with respect to their relations as they are integrated into memories of situations. Increasingly smaller amounts of orientation in the present, making for a greater degree of vividness of the subjective reproduction of objective experiences and correspondingly increased degrees of inaccuracy of the relations of their elements, constitute imagery and hallucination. It will be recalled that the structure of the foregoing definitions is built on the physiological and anatomical fact that the cessation of activity of a link in the nerve pathway results in a flaring up of the function of the nerve-link which succeeds the former in the normal direction of nerve conduction. At this point we are confronted with the question regarding the causes of such an occurrence. The assumption that an injury of a receptive area of the cerebrum is productive of hallucinations, because of its irritating effect on the contiguous association systems, is invalidated by the fact of the occurrence of hallucinations and of the allied phenomena of imagery and thought in the state of attention and in the onset and termi-

CONCLUDING

REMARKS

nation of normal sleep. We are thus thrown back on the theory of the release of the essential function of a link in the nerve pathway when the activity of the link which precedes it in the direction of nerve conduction has ceased. The theory of release does not, however, solve the problem. For there still remain the questions: By what means does the activity of the receptive nerve apparatus inhibit the activity of thought, imagery, and hallucination? By what means does the activity of the association systems, manifested in thought, inhibit that of the emotional mechanism of the thalamus? By what means does the motor mechanism of the cerebral cortex diminish the activity of the spinal mechanism of the patellar reflex? And so forth. A hope for a possible answer to these questions lies in the recent advances in the understanding of the action of certain chemical substances, formed at some nerve endings as a result of the arrival of nerve impulses. If it can be shown, for example, that the result of the arrival of nerve impulses at the sensory receptive areas of the cerebrum is the production, at the points contiguous with the association systems, of chemical substances which have a disabling effect on the latter nerve systems, the foregoing questions will in great measure be answered. Moreover, if such can be shown to be the case, the problems involved in the chronic states of disorientation—the bane of the educator—accompanied by hallucinations and catatonia in certain dementias, may likewise be largely solved.

INDEX Acetylcholine, JJ, M Adams, Francis, 8 Adler, Edmund, 229, 230, 267 Adrenal cortex, 60 Adrenal medulla and Adrenin, 2 6, 54, 58, 60,

6S,

93

Adrian, E . D . , 109, 1 1 2 Adson, A l f r e d W . , j 8 , 66 Alcmaeon of Crotona, 4 Alcohol, 8, 82, 187, 240, 256, 260 Alpers, Bernard J., 165, 170 Amnesia, 162, 163, 199 A n a l o g y , 142 Anaxagoras, 5 Anesthesia, 14, 17, 26, 77, 247, 256-59 A n g e r , 22, 55, 58, 92, 93, 211 Anrep, G . V., 152, 223 Anxiety, 3 1 - 3 3 , 52, 61, 62, 83, 235, 236 Aphasia, 122, 199, 253 in dreams, 248, 249 in recovery from epileptic seizure, 178 motor, 8, 1 1 7 , 118, 120, 121, 157 sensory, 1 1 6 , 1 1 7 , 120, 157 substitution of words in, 248, 249 Apprehension, 31, 97, 137, 174 Archambault, L a Salle, 158, 169 Areas of cerebral cortex, 77, 78, 1 2 1 , 165 motor ( F i g . 5 A , p. 1 1 9 ) , 118-20, 157, 1 7 6 - 7 8 , 180, 259, 260, 262, 263 j injury to, 157 sensory receptive, 42, 48, m , 1 1 5 , 1 1 6 , 118-20, 155, 245, 259, 2715 injury to, in relation to hallucination, 77, 1 1 4 , 1 5 7 69, 270; of contact, 1651 of hearing, 77, 120, 158, 165, 1 6 7 ; of smell, 1 1 8 , 120, 158, 165, 1 6 7 ; of taste, 1 1 6 , 120, 158, 1 6 5 ; of touch, n 6 , 1 1 8 ; of vision, 77, 116, 1 1 8 - 2 0 , 158, 164, 165, 167, 168 Aristotle, 4, 5, 8 Aron, Hans, 225, 266 A r t , 129, 149, 151 definition of, 148 in relation to illusion and delusion, 249 Arteriosclerosis, 67, 162, 163 Asphyxia, 55, 251

Association and Associative apparatus, 13, 63, 64, 90, 9 1 , 97, 173, 256, 262 Association systems ( F i g . i E , p. 4 1 ) , 82, 84,

hi activity o f , in imagery and dreams, 225, 264, 2701 in sleep, 2 3 5 - 3 7 , 245-47, 262, 2 6 3 ; in thought, 222, 223, 235, 236, 245, 262, 263, 271 arcuate ( F i g . 5 F , p. 1 1 9 ) , 118, 120, 165 complete suspension of activity of, 1 7 4 - 7 8 , 245, 163 defective functioning o f , in relation to activity of cerebral efferent systems, 1 7 4 - 7 9 , 220, 2 2 1 , 223, 245, 262, 263 ¡ to activity of thalamic mechanisms, 1 7 3 - 7 5 , * i o ~ 2 3 i 237, 262, 263, 2 7 1 ; to imagery and hallucination, 164-69, 1 7 3 - 7 5 , '77> '79> 180, 220, 221, 223, 256, 263, 270, 271 ; to vividness, 167-69, 1 7 3 - 7 5 , 180, 236, 237, 262, 263 inferior longitudinal fasciculus ( F i g . 5 H , p. 1 1 9 ) , 120, 165 injuries of, 77, 1 1 3 , 1 1 5 - 2 1 , 157, 168 modification of, by nerve impulses, 7 9 - 8 1 , 125, 202, 271 myelination o f , 109 the repository of memory, 77, 78, 1 1 5 - 2 2 , 1 6 7 - 6 9 , 235, 236 uncinate ( F i g . 5G, p. 1 1 9 ) , 118, 120, 165 Atropine, 82 Attention, 169, 1 7 1 , 210 breach in, made by strong stimuli, 187, 188, 207, 222 concentration of, 215 dominance of, by selected sensations, 182, 187, 188, 190-96, 201, 202, 204-6, 2 1 1 , 2 1 5 , 2 1 9 - 2 2 ; accompanied by emotion, 192, 203-5, 2 I I > 2 Z I > 2 2 2 ; and feeling, 183, 184, 186, 187, 190-92, 204-6, 2 1 1 , 221-23 effect of drugs on, 258-60 factors of clarity and intensity in, 220-23 fixity o f , 192 fluctuation

o f , 1 9 1 , 192, 221

204-6,

274

INDEX

Attention (Continued) in relation to imagery and hallucination, «55» «57» «68. »07-9. » " - « 4 » 1 1 6 . i i 7 ) 220, 222; to learning, 1 9 5 - 2 0 1 ; to mental attitude, 201-4, 214, 2 1 5 ; to mimesis, 193-95, 200, 201, 203, 204; to sleep, 192, 209-14, 216, 2 1 7 , 220-22, 246, 2 6 J ; to suggestion, 2 1 1 - 1 5 , 222} to thalamic functions, 220-23 j to thought, 155, 157, 168, 207, 208, 2 1 5 - 1 7 , 220, 222, 270; to training and heredity, 207, 208, 215, 216 mental index of bodily needs, 183-88, 19096, 202, 204-6, 2 1 1 , 214, 215, 221, 222 muscular manifestations of, 2 1 7 - 2 1 , 223 orientation in, 183, 185, 192, 200, 201, 205, 210, 2 1 1 , 2 1 5 - 1 9 relation of stages of, to nerve pathway, 219-23, 237 Autonomic nerve system (Fig. 1, p. 4 1 ) , 5060, 63, 65, 67, 78, 81, 85, 93, 96-98 control of, by cerebral cortex, 5 1 - 5 3 , 59, 65, 81, 82, 84, 85 effect of drugs on, 55, 65, 82, 85, 86, 96 effects of, on cerebral cortex, 67, 68 functions of, 58, 59, 69, 189 in epileptic seizure, 175 in relation to emotion, 5 1 - 5 5 , 58, 59, 6 1 64. «5. 93» 97» 98} to sleep, 69, 227, 228, 241 ; to skeletal musculature, 55, 56, 58, 65, 68, 85, 86, 232, 233; to smooth musculature, 48-50, 52-60, 65 local activities of, 56-59, 64, 65 mid-autonomic division of (Fig. 1 , p. 4 1 ) ; abnormal stimulation of, 58) effect of oxygen-deprivation on, 53, 54; local paralysis of, 53, 57; reinforced by adrenin, 54, 55, 58, 60, 65 reciprocal action of antagonistic divisions of, 51-55» «S same action of, in different bodily states, 55, 56, 63-66 substitution of functions of, by cerebral cortex, 189 Axenfeld, Th., 169 Babinski, sign of, 177, 180, 226, 227, 263 Bacon, Francis, 5, 9 Bailey, A. A., 181 Bailey, Perei val, 229, 230, 268 Ballard, Charles W., 269 Bamberger, J . , 224, 265 Barbital compounds, 230, 256, 260

Bard, Philip, 98, 102 Barenne, Dusser de, 26, 38, 86, 101 Barris, R. W., 230, 269 Baruk, Henri, 123 Bass, E., 225, 266 Bastedo, Walter, 269 Beattie, J., 230, 269 Beevor, Charles E., 181 Bell, Charles, 130, 151 Belladonna, 256 Bertrand, I., 229, 268 Bickel, Adolf, 39 Bierce, Ambrose, 251, 269 Blankenhorn, M. A., 224, 266 Blindness, 77, 158-61, 164, 166, 168, 169, 171» «74 Bliss, A. Richard, 269 Blood, 4, 60-62, 93, 261 circulation of, 5 coagulation of, increased by adrenin, 54, 65 distribution of, regulated by mid-autonomic, 5 2 - 54> J» in sleep, 225 oxygenation of, 5 3 quantities of, in cerebral cortex, 67 Blood pressure, 26 in unconsciousness and muscular relaxation, 227, 228 lowered in sleep, 224, 225, 227, 228 raised by exciting dreams, 224, 225 regulated by mid-autonomic, 53, 54 Blood vessels, 92 cerebral, 67 of brain of puppies, in sleep, 225 of salivary glands, 52 regulated by autonomic system, 48, 50, 5255» 57» «5» 67. 68» 78 superficial, 96; in muscular exertion, 35, 36, 53» 55-57» in sleep, 225 visceral, 54-56 Blushing, 53, 59, 82 Boas, Ernst P., 224, 265 Bodily needs, 104 acquired, 9 : , 150, 185-87, 189-92, 240 cerebral activity in relation to, 190, 204, 205 determining mimetic reactions, 193, 194, 214, 215 in relation to attention, 183-88, 190, 1 9 1 , 196, 202, 204-6, 2 1 1 , 214, 215, 2 2 1 , 222 inherited, 58, 62, 69, 91, 92, 145-47, 150, 1 5 1 , 183-85, 187-92, 195, 239, 240

INDEX Bodily needs (Continued) precedence of auxiliary over basic ones, 185, 187, 189 lignaled by feelings, 91, 183-88, 190-92, 204-6, 211, 220-23, J 4°> resulting in domination of corresponding sensations, 91, 145-48, 182-88, 191-94, 201-6, 211, 215, 221 wavelike course of, 186, 187, 192, 194, 214, 240-42 Body oscillating balance of, 59-63 ; in relation to autonomic system, 63, 64, 69; to cerebrum, 67, 68, 75 ; to thalamus, 69 permanence of changes of, in relation to emotion, 63, 64, 90, 91 Bogen, H., 33, 39 Brain, 4, 6, 13, 27, 40, 81, 93, 98, 109 abnormality of, in relation to mentality, 8, 157-69; to pathologic laughing and crying. 95 vascular disease of, 95 vegetative centers of, 228 volume of, in sleep, 225 Brain stem, 40-42, 49, 56, 57, 78, 79, 87, 98, 108, 157, 177, 227, 245, 264 Brickner, Richard M., 123 Britton, S. W., 26, 38, 58, 66, 93, 101 Broca, P., 117, 122 Bromides, 256, 259, 260 Brooks, Harlow, 224, 266 Brow, G. R., 230, 269 Brown, George E., 58, 66 Brown, Horace, 8 Brown, T . Graham, 69, 100, 125, 151 Buckle, Henry Thomas, 7, 9 Bullough, Edward, 9 Calcarine fissure (Fig. 5, p. 119), 120, 158, 164, 165 Campbell, H. E., 224, 266 Campbell, James Argyll, 225, 266 Cannabis indica, 256, 259 Cannon, Walter B., 26, 31, 32, 38, 39, 58, 63, 66, 86, 93, 101, 130, 151, 152, 183, 223 Cardio-vascular disease, 224 Carlson, Anton Julius, 225, 226, 266, 267 Carlyle, Thomas, 151 Carpenter, William B., 143, 152 Carroll, John H., 224, 266 Cataplexy, 230 Catatonic state, 192, 271

275

Cato the Censor, 224, 265 Central nervous system, 40, 43, 49, 54, 57, 68, 69. 76» 78, 81, 83, 84, 99, i n , 176, 260 Cerebellum, 175, 178 Cerebral reflex arc, 178, 180, 221 Cerebrocerebellar system, 175, 180 Cerebrospinal system or tract (See Pyramidal tract) Cerebrum, human, 13, 25, 69, 76, 80, 84, 86, 95, 111, 112, 115, 116, 118, 121, 130, 1 73 _ 75> >8°> *34, 239, 245, 256, 271 activity of, in relation to bodily needs, 190, 204, 205 an integral part of the body, 67, 68, 75, 99 association systems of (See Association systems) efferent systems of (See Nerve systems, cerebral) motor area of (See Areas of cerebral cortex) motor functions of, 220, 221, 223 nerve impulses of (See Nerve impulses) prefrontal region of, in relation to reason and judgment, 121, 122 sensory receptive areas of (See Areas of cerebral cortex) substitution of functions of, for those of autonomic system, 81, 82, 188-90 Cerebrumless animals, responses of, 26-28, 38, 43> 45 Cerebrum of animals, 26-28, 43, 69, 175 Chain reflex, 147, 151 Chloroform, 256-258 Circulatory system, 36, 225, 228, 232, 261 Clark, W. E. LeGros, 70, 101 Claude, Henri, 229, 267 Clidemus, 5 Clodd, Edward, 151 Cloetta, M., 230, 268 Clonus, 94, 226, 263 Cobb, S., 181 Codeine, 258 Cognition, 88, 89, 96, 98, 100 (See alto Knowing) Coma, 51, 178 Comparisons, 114, 139, 249, 264 Comprehension, 121, 157, 178 Conditioning (See Training) Consciousness, 3, 6, 19, 20, 37, 70, 89, 93, 113, H4> 121, 158, 159, 166, 171, 172, 177-179, 181-83, ' 9 ' j 222, 257 (See also Sensory or informative state) dominance of, by selected sensations, 184-87, 190-92, 205, 215

27 6

INDEX

Consciousnes* (Continued) relation of, to emotions, 4.0-66, 155 semi-conscious state, 259 unconsciousness, 3, 166, 173, 175, 177, 178, 1 8 1 , 192, 205, 2 1 5 , 2 i i , 2 j t , 257» >n relation to heartbeat, blood pressure, and respiration, 227, 228; in sleep, 224, 228, *5 2 » 1 5J» »J«. *$9> *6Ji startle, 179 Convolutions, angular, 120; frontal, 120; postcentral, 1 6 5 ; precentral, 157; supramarginal, 120; uncinate, 174 Convulsions, caused by insulin injection, 6 i ; in epileptic seizures, 40, 166, 1 7 1 , 1 7 5 - 1 7 8 , 181 Cortex, cerebral, 46, 65, 86, 177, 215 association apparatus or systems of (See Association systems) associative functions of, 30 cognition, a function of, 96, 98 control of thalamic functions by, 74, 75, 79> «4) >03 destruction of, in relation to emotion, 25, 26, 43 effect of autonomic system on, 67, 68) of degeneration of, 81, 82; of experimental removal of, 26; of picrotoxin on, 82, 8 5 - 8 7 ; of severance of nerves connecting thalamus with, 69-74 functions of, in relation to autonomic system, 51-53» 59» 65, 81, 82, 85, 86, 2 4 1 ; to clarity of sensation, 96, 98, 100, 204, 205, 222, 2 2 3 ; to emotions, 29, 30, 38, 5 1 , 52, 81-84, 89, 90, 96-100; to hallucination, 221, 223, 242; to onset of sleep, 241, 262; to patellar reflex, 2 7 1 ; to sensory impulses, 40-42, 48, 49, 64, t0 67» 70, 74» 76-85» 87» 89» 99» skeletal musculature, 23-30, 84-86, 103, 105-7, 157, 2 2 7 ; to thalamic activity, 25-27» 29» 69-7«» >73» >75» 180, 104» 205, 220-23 inactivity of, in relation to muscular rigidity» >75» 152» 163 motor areas of (See Areas of cerebral cortex) nerve pathways of, 67, 77, 79, 80, 84, 89, 95» >*5» *5>. * 5 2 sensory receptive areas of, in relation to hallucination, 77, 1 5 7 - 1 6 9 (See alio Areas of cerebral cortcx) substitution of functions of, for those of autonomic system, 81, 82, 188, 189 will, a function of, 108

Corticospinal and corticobulbar system (See Pyramidal tract) Corticothalamic system (See Nerve systems) Cox, Leonard, 229, 268 Cretinism, 61 Curella, H., t o i Cushing, Harvey, 158-60 (cases), 165, 169 Cushny, Arthur R., 269 Dameshek, William, 66 Dana, Charles, 97, 102, 228, 267 Daremberg, Ch., 9 Darwin, Charles, 7, 66, 130, 151, 269 Davison, Charles, 95, 102 Deafness, 77, 88, 161, 169, 172 Delinquency, 157 Delusion, 148, 150, 1 5 1 , 203, 204 relation of, to illusion, 148, 180, 249, 2 5 0 »65 Dementia, 81, 94, 271 Democritus, 5 Demole, V., 230, 268 Depression, 32 Descartes, René, 6, 9 Diabetes, 61 Diacetyl-morphine, 258 Digestion apparatus of, 30-32, 34, 35, 38, 52, 55, 62, 82, 189, 225 arrest of, during strong emotion, 30-34, 55, 62 in sleep, 225 Digitalis, 82 Diogenes, 5 Diplegia, facial, 94 Diplopia, 246 Disorientation, 155, 161, 168, 209, 212 in catatonic states, 192, 2 7 1 ; in epileptic seizure, 1 7 1 - 7 4 , 1 7 7 - 8 1 ; in lower animals, 208; in normal epileptoid reaction, 179; in onset of and awakening from sleep, 209, 2 1 1 , 226, 234, 245, 253-56, 261, 263 under picrotoxin, 85, 86 Dixon, Walter E., 269 Dizziness, 166; in epileptic seizure, 1 7 1 , 173, 246 Draganesco, St., 229, 268 Dreams, 13, 157, 163, 270 (See also Hallucination) as mental index of state of body, 239-42 based on representations and symbols, 127, 212, 238, 239, 242

I N D E X Dreams (Continued) confusion of likeness w i t h identity in, 249, 250, 264, 265 in epileptic seizure, 1 7 7 in n o r m a l sleep, 1 5 7 , 1 6 8 , 209, 2 1 0 , 2 1 7 , 224, 227, 2 3 8 - 4 $ , 2 4 8 - 5 3 , 264, 2 6 5 ; different in f a l l i n g asleep a n d o n a w a k ening, 2 5 3 ; d u r a t i o n o f , 250, 2 5 1 ; effect of f a u l t y conception of relations on, 243, 244, 264, 2 6 $ ; effect o f , on f u t u r e behavior, 2 5 1 , 2 5 2 , 2 6 5 ; e m o t i o n a l factors in, 224, 225, 2 3 7 , 2 4 2 ; of f a l l i n g f r o m a height, 244, 245 ;• orientation in, 208, 209, 238, 239 ; r e c u r r i n g , 2 4 0 - 4 2 , 2 4 4 ; sexual, 2 4 1 , 2 4 2 ; startle in, 244, 2 4 $ ; substitution of words in, 248, 249 in sleep produced by d r u g s , 1 5 7 , 2 j 8 , 259 Drugs effect 82, habit, Dunbar,

of, on nervous system, 1 4 - 1 7 , 55, 6 j , 85, 86, 96, 256, 260, 265 187, 240 H . F . , 32, 39

E c o n o m o , Constantin von, 76, 1 0 1 , 228, 229, 267, 268 E d i n g e r , L., 25, 38 Education, 128, 129, 1 3 1 E f f e r e n t systems, cerebral ( S e e N e r v e systems) Emotions, 2 1 3 , 220, 2 2 2 , 257 bodily changes in, 3 0 - 3 8 , 5 1 - 5 5 , 58, 62, «5, 9 2 > 93, 96, 97 "disagreeable," 26, 28, 33 dissociation of feeling o f , a n d expression of, 9 7 ; in pathological cases, 9 3 - 9 5 ; and under action of drugs, 96, 97 expression of ( S e e Expression) feeling of (See F e e l i n g ) f o u r factors of, 96, 1 0 0 function o f , in redistribution of bodily energies, 2 1 - 2 3 intensity of, in relation to sensation, 2 4 - 2 9 ; in acephalic infants, 2 5 ; in acortical animals, 2 6 - 2 8 , 3 8 ; in a n i m a l s with sound cerebral cortex, 2 4 - 2 6 , 28, 29, 3 8 ; in decorticated animals, 25, 26, 28, 2 9 ; in disease of thalamus, 6 9 - 7 4 ; in idiots, 25, 2 6 ; in n o r m a l infants, 25 J a m e s - L a n g e t h e o r y o f , 6, 92, 93, 1 0 0 manifested by m o v e m e n t a n d posture, 6 9 7 1 , 8 2 - 8 4 , 93, 94, 9 6 , I O O > I 3 J - 4 1 , 194. 195, 2 1 1 mechanism o f , in relation to cortical activ-

277 ity, 25t 1 9 , 3«, 5 1 » J » , * i , 1 4 " , » 4 » , 2 6 2 , 2 6 3 ; to m e m o r y , 9 6 - 9 9 n e r v e systems responsible f o r bodily changes

>n, » 9 , 37, 4 8 - 5 6 , 5 * , 59, 6 1 - 6 4 on level b e l o w t h a l a m u s , 89, 98, 99, 2 2 2 p e r m a n e n c y of effects o f , 3 7 , 38, 63, 64, 78, 90, 9 1 , 1 3 0 , 1 3 1 , 240, 250, 2 5 2 , 265 physical basis o f , 1 9 - 2 1 , 37 relation o f , to conscious state, 4 0 - 6 6 ; t o sensation, 1 9 - 2 1 , 2 4 - 2 6 , 4 0 - 6 6 , 7 0 - 7 4 , 88-92, 192, 2 0 3 - 5 seat o f , 3 t h a l a m i c mechanism o f , 69, 74, 79, 89, 90, io 3 , 1 7 3 , 1 7 5 ; in sleep, 2 2 7 ; manifested by intensity of feeling, 98, 1 7 5 , 180, 220, 222, 223, 237, 241 Empedocles, 5 Encephalitis l e t h a r g i c a , 2 2 8 , 2 2 9 Endres, Gustav, 2 2 5 , 2 6 6 Epileptic seizure, 3, 4, 1 5 5 causes o f , 1 7 3 convulsions in, 166, 1 7 1 , 1 7 5 - 7 8 , 1 8 1 ; in relation to receptors, 40 definition o f , 171 dilation of pupil in, 5 1 disappearance of t e n d o n reflexes in, 1 7 7 disorientation in, 1 7 1 - 7 4 , 1 7 7 - 8 1 d u r i n g operation on skull, 67 f o r m s o f , 1 6 5 - 6 7 , 1 7 1 , 1 7 3 - 7 6 , 1 7 8 , 180, 1 8 1 ; Jacksonian, 1 7 1 , 178, 179, 1 8 1 ; major, 1 7 1 , 175, 178, 2 5 3 ; minor, 159, ' 7 ' , 173, «74, «78, »8«, 2 5 3 , n o r m a l epileptoid o r s t a r t l i n g reaction, 83, 1 7 9 , 1 8 1 ; psychic equivalent, 1 7 1 ; r e c u r r i n g , ' 7 3 , ' 7 4 , t e m p o r a l fit, 1 6 7 ; uncinate fit, 165, 174 hallucinations in,

159,

160,

165-67,

171-

74. 177, 179, 180, 2 5 3 loss of consciousness in, 166, 1 7 1 - 7 3 , 1 7 5 , 177, 178, 181 mechanism o f , 1 7 1 - 8 1 , 2 2 1 , 245, 246 p a r o x y s m a l outcry o f , 1 3 6 p r e m o n i t o r y symptoms o f , 1 7 1 - 7 4 , 246 recovery f r o m , 1 7 7 , 1 7 8 , 180, 1 8 1 sign of Babinski in, 1 7 7 , 1 8 0 E r l a n g e r , J o s e p h , 109, 1 1 2 Esterase, 5 5 , 111 Ether, 256, 2 5 7 Ethylene, 14, 256 E v o l u t i o n a n d Dissolution of the N e r v o u s System, L a w o f , 8, 1 3 , 1 6 - 1 8 , 1 2 1 , 1 2 2 , 204, 246, 2 5 7 , 2 5 9 , 262, 264 E x c r e t i o n , 228, 233, 2 6 1

278

I N D E X

Expression, 1 6 , 3 0 , 2 4 8

Field of vision, 1 5 8 - 6 0 ,

by means of comparisons, of

interjection,

1 3 9 , 141,

1 3 7 , 138;

of

142;

imitative

sounds, 1 3 8 , 1 3 9 (See Emotions)

of emotions, 2 0 , 2 j , 3 7 , 5 8 , 6 7 , 7 0 , 8 3 , 8 5 , 86,

8 9 , 9 2 , 9 3 , 9 8 , ioo} or

1 6 2 , 164, 166,

167,

172, 174, 205

Fischer, B., 2 5 , 3 8 Fischer, H . , 2 3 0 , 2 6 8

dissociation of feeling and

visceral

168,

vascular

in absence

activity,

93-97;

Flechsig, P a u l ,

18, 109, 1 1 2

Foerster, O . , 2 2 9 , 2 6 8

of

Français, H e n r i ,

in

Frazier, C h a r l e s H . ,

229, 267 165, 170

defect of cerebral cortex, 2 5 , 2 6 , 2 8 , 2 9 ,

Fulton, J . F . , 2 2 9 , 2 3 0 , 2 6 8

8 1 , 8 6 , 9 7 ; in disease of thalamus, 6 9 - 7 4 ,

Functions, 6 1 , 6 9 ; evolution or loss o f , 6 , 7 ,

98,

99, 204

Exultation,

43.

'37.

*3«>

22, 137, 241 Galen, 5 Gagel, O., 2 2 9 , 2 6 8

Faith " c u r e , " 2 1 4

Gaskell, W .

F a r r , C l i f f o r d B., 3 2 , 3 9 Fatigue,

2 3 3 , 2 5 5 ; of

skeletal

musculature,

Geniculate b o d y , 1 5 8

reduced by adrenin, J 4 , 6 j Fear, 2 2 , 5 2 , 5 5 , 5 8 , 8 1 , 8 j , 9 7 , 1 3 6 , 1 3 7 ,

Gibbon, E d w a r d , 2 8 , 3 9 , 2 1 2 , 2 2 3 , 2 4 8 Gilson, ¿ t i e n n e ,

• 47

Glands and G l a n d u l a r activity, 3 6 , 4 0 , 4 5 , 4 8 ,

15, 20

a mental index of internal disturbance, 2 0 , 37.

2

a thalamic 205,

function, 8 9 , 9 6 , 9 8 , 9 9 , 2 0 4 ,

220-23

correlation o f , with memories, 9 6 , 1 0 0 , 1 8 3 , 184 of expression and

in pathological

49. 5 2 - 5 4 > 60, 6 1 , 6 5 , 68, 78, 7 9 , 9 6 , 1 8 3 , 250 Glaucoma,

162

Goldstein, K . , 1 1 7 , 1 2 3 Gollwitzer-Meier,

cases, 9 3 - 9 5 ;

feeling, 9 7 ; and

under

certain drugs, 9 6

Kl.,

225, 266

Goltz, F., 2 5 , 3 8 , 8 6 , 1 0 1 , 1 0 $ , Government,

definition o f , 8 8 , 8 9 dissociation

9

Githens, T h o m a s S., 2 6 9

in epileptic seizure, 5 1 , 1 6 6 , 1 7 4 Feeling,

H . , 66

Gasser, Herbert S., 1 0 9 , 1 1 2

tot

129, 140, 141, 149

Gowers, Sir W i l l i a m R . , 2 4 5 , 2 5 2 , 2 6 9 Greef, 1 6 9 Guillain, G . , 2 2 9 , 2 6 8

in dreams, 2 4 1 , 2 4 2 in epileptic seizure, intensity

of,

166, 172-75

96, 98-100,

112, 114, 115,

1 7 5 , 1 8 0 , 2 0 4 - 6 , 2 2 1 - 2 3 , 2 3 7 ; dependent on intensity of internal disturbance, 1 8 6 ; on intensity of bodily need, 6 2 , 1 8 7 , 1 8 9 , 2 0 5 , 2 0 6 , 2 3 9 ; and on strength of stimulus, 2 2 2 ; in disease of thalamus,

71-74,

204 of

emotion,

20, 37,

reasons f o r dominance of certain feelings at 190-92,

205, 206 relation o f , to k n o w i n g ,

8 9 , 9 0 ; to sensa-

tion, 8 9 - 9 2 , 9 9 , 1 0 0 , 1 1 3 , 1 1 6 ; to sensory receptor organs, 9 1 , 9 2 signaling a specific internal disturbance, 8 9 , 90, 9 2 , 9 6 - 1 0 0 ,

192, 204, 205, 2 1 1 ,222

significant of vague orientation, 8 9 , 1 0 0 under action of drugs, 9 6 , 9 7 , 2 4 0 Feeling-tone,

221, 223

186, 187

Haldane, J. B. S., 2 2 5 , 2 6 6 Hallucination, (See

13, 14, 19, 89, 1 1 5 , 1 2 7 , 271

also

Dreams)

a mental index of a corresponding state of the b o d y , 2 4 0 , 2 4 2 as a

of

result

concentration

of

attention,

211-13

89-100

any one time, 1 4 6 , 1 4 7 , 1 8 3 - 8 8 ,

Habit, physiological significance o f ,

conditioned by diminished sensory reception, >55-58.

172, 173, 179, 180, 207, 208,

210-13,

" J . 233. 234, 237,263;

and consequent f a u l t y activity o f association systems,

164-69,

173-75,

' 7 7 . t79.

180 confusion of likeness with identity in, 1 8 0 , 249,

264, 265

definition o f ,

155, 156, 262, 270

duration o f , 2 5 1 effect o f , on future behavior, 2 5 1 , 2 J 2

INDEX Hallucination (Continued) elaborate, 159, 160, 162-69, 1 73> ' 7 + in destruction of sensory receptive area of cerebrum, 1 1 5 , 1 5 8 - 6 1 , 165-69, 270; in injury or disease of sensory nerves, 15S, 1 6 1 - 6 J , 1 6 7 - 6 9 ; or sensory receptors, 161, 162, 1 6 7 - 6 9 ; in temporary functional sensory disturbances, 163, 164, 168, 169 in epileptic seizure, 159, 1 6 5 - 6 7 , 1 7 1 - 7 4 , 179, 180, 253 in relation to sleep, 207, 2 1 1 - 1 3 , 2 2 Z > 2 3 7 39) *44> 24S> 252, 2 5 3 - 5 7 , 259, 2 6 1 - 6 3 , 2 6 5 ; to thought, 6, 7, 207-9, 216, 22023, 262, 2 7 0 ; to training and heredity, 216, 217 least accurate and most vivid of mental functions, 156, 180, 2 6 1 - 6 3 , 270 localized in hiatus of sensory field, 158-69, 172-74 mechanism of, 157-69, 270 of contact, 159, 160, 165, 167, 1 7 1 - 7 3 ; of movement, 1 6 6 ; of sense of balance, 166, 1 7 1 , 1 7 3 ; of smell, 159, 160, 165-67, 173, 1 7 4 ; of sound, 161, 167, 169, 172, 1 7 3 ; of taste, 159, 165, 168; of temperature, 1 6 7 ; of vision, 159-69, 1 7 1 - 7 4 , *S4> 255 recurring, 173, 174, 240-42 seat of, 4 simple, 161, 162, 168, 169, Harvey, William, 5 Haupt, Istar A . , 101

171-74

Head, Henry, 70, 7 1 - 7 4 (cases), 122 Heart, 4, 53, 82, 97, 232 Heartbeat

101,

117,

in exciting dreams, 224; in sleep, 224, 2 2 7 ; in strong emotions, 35, 52, 147 in relation to autonomic system, 5 2 - 5 4 ; to muscular activity, 52, 227, 228, 232, 233; to thalamus, 7 8 ; to thyroid secretion, 61 Hechst, Béla, 229, 268 Hemorrhage, 69, 1 1 6 , 178 Henschen, Salomon Eberhard, 158, 165, 169 Henschen's loop, 165 (See also Optic radiation and Meyer's loop) Herr, K . , 225, 266 Hess, W . R., 53, 66, 230, 268 Hett, W . S., 8 Hippocrates, 4 Hirsch, Erwin, 229, 230, 267

279

Hogner, P., 229, 268 Hollingworth, H. L., 149, 150, 152, 1 2 4 , 265 Holmes, Gordon, 70, 7 1 - 7 4 (case*), 101 Holtz, P. R., 181 Homeostasis, 143, 183 Horrax, G., 164 (cases), 170 Hugo, Victor, 94 Hume, David, 6, 7, 9 Hunger, 91, 144-481 150, ' J ' . i9'> >94. »95. 241 Hyoscine (or scopolamine), 226, 256 Hyperpnoea, voluntary, 175 Hypnotism, 2 1 3 - 1 5 Hypothalamus ( F i g . 1, p. 4 1 ) , ( F i g . 1 1 , p. 2 2 8 ) , ( F i g . 12, p. 2 2 9 ) , 48, 95 contains highest autonomic centers, 65, 69. 98, 204 cortical control over autonomic functions o f , 262 effect of stimulation or injury of, 230; productive of sleep disturbances, 228-30; and of other autonomic disturbances, 69, 70 Hysteresis, 233

Indigestion, 31, 32 Idiocy, 25, 157 Ilin, M . , 134, 151 Illusion, 148; relation of, to delusion, 148, 180, 249, 250, 264, 265 Imagery, 19, 89, 127 a mental index of a corresponding state of the body, 240, 242 conditioned by diminished sensory reception, ' 3 . 14. 155. IJ6. 207-9, 2 1 1 - 1 3 , 220, 222, 234, 263 confusion of likeness with identity in, 249, 264, 265 definition o f , 155, 156, 262, 270 in relation to sleep, 236, 237, 244, 245, 252, 253, 2 6 1 - 6 5 ; to structure of cerebrum, 157, 168; to thought, 155, 156, 207-9, 2 1 1 , 213, 216, 220-23, 235, 2 6 1 63. 265, 270 reasons for recurrence of, at certain times, 240 Imitation (or Mimesis), 1 1 7 in animals, 193-95 in relation to bodily needs, 1 9 3 - 9 5 ; to inherited and acquired traits, 1 9 5 ; to mental attitude, 201-4, 2 1 4 ; to scope of attention, 193-95

28o

INDEX

Imitation (or Mimesis) (Continued) intermediary stimuli in acts of, 1 9 j , 196, 200, 201, 213, 214; their effects, 201, 203,

204,

213-ij

learning by, 195, 196, 200, 201 mechanism of, 65, 193-96, 2 1 3 , 222 motives for, 193, 194 of natural sounds in spoken language, 138, •39 Inaba, Ch., 230, 268 Infundibulum, 228, 230 Ingram, W. R., 230, 269 Insanity, 3, 4, 157 Intercortical pathways (See Association systems and Nerve pathways) Interjection, 116; representative of emotion, 136-38

Intoxication, 204; alcoholic, 8, 82, 187, 240, 257» 16° Jackson, J . Hughlings, 8, 9, 13, 18, 121, 122, 174, 181 Jacobson, Edmund, 223, 226, 267 James, William, 92, 101, 130, 151, 216, 223 Jennings, H. S., 126, 130, 151 Johnston, Robert L., 225, 266 Judgment, 8, 13, 22, 213, 216, 2J7 loss of, in disease of prefrontal region, 1 2 1 ,

Laughter, 95, 194, 1 9 5 ; pathologic, 93-95 Lea, Henry Charles, 108 Learning, 189 by imitation, 195, 196, 208; by means of intermediary stimuli, 195, 196; by trial and error, 195, 208 effect of general experience on, 200, 201 implies increased adjustment to surroundings, 45, 64, 81 ; under varied conditions, 199,

200,

208

in relation to size of cerebrum, 81 ; to will, 107

persistence of most appropriate reaction in, 196-99

Lee, M a r y A . M . , 226, 266 Lesses, Mark F . , 66 Lewis, J . T . , 58, 66, 93, 101 Leyton, A . S. F . , 176, 1 8 1 Lhermitte, J . , 229, 267 Lobes, cerebral ( F i g . 5, p. 119) frontal, 118, 120; occipital, 120, 158, 164671 parietal, 1 6 5 1 temporal, 110, 158-60, 164-67,

174

Loman, Julius, 66 Long, C . N . H., 230, 269 Lucas, Keith, 101, 109, 112 Lucksch, Franz, 229, 267 Lueders, Charles, W., 32, 39

122

under action of drugs, 2J7-J9 Justinian, 28 Juvenal, 248 Kanner, Leo, 224, 266 Keeser, E., 230, 268 Keeser, J . , 230, 268 Kekule, August, 2 1 6 , 223 Kelman, Harold, 95, 102 Kennedy, Foster, 100, 165-66 (cases), 170 Kincead, B., 151 Kleist, K., 229, 268 Kleitman, Nathaniel, 224-26, 265, 266 Knowing, relation of, to feeling and sensation, 89,

90,

222

Kreindler, A., 229, 230, 268 Kroetz, Chr., 225, 266

McBride, Katharine E., 117, 123 MacWilliam, J . A., 224, 266 Marinesco, G., 229, 230, 268 Mauthner, L . , 228, 267 Medulla oblongata, 260 Memory, 45, 124, 183-85, 196, 199-201, 215, 216, 2 1 7 - 1 9 , 238, 239 (See also Recall) accuracy of pattern of, dependent on orientatation in present and immediate surroundings, 155, 156, 270; and its correlation with past, 88, 89, 98-100, 156 biological significance of, 208, 209 determining volitional acts, 86, 87, 104-7, 210, 2 1 1 , 221,

guided Lafora, Gonzalo R., 230, 268 Lambert, Ruth, 66 Lange, Carl Georg, 6, 92, 93, 101, 130, iji Language, gesture, 135, 136, 141; spoken, 136-40, i 4 9 i written, 1 3 2 - 3 5 , 141, 149 Lashley, K . S., 89, 101

227

disintegration of,

212,

223,

by sensory 217,

120-22,

245-50, 222,

168,

173,

220,

206-8,

211,

264

receptors, 223

in relation to bodily need, 1 5 0 ; to emotional mechanisms, 96-100; to mental attitude, 201, 202 modification o f , by internal and external conditions, 1 1 5

INDEX Memory (Continued) of the elements of a situation, 16, 1 7 , 77, 78, 1 1 3 - 1 1 5 , 1 1 8 , 156, 1 6 7 , 1 6 8 , 206-8, 243-461 164 permanence of effects of, 63, 64, 7 7 - 8 0 , 90, 1 3 0 , 1 3 1 , 240, 2 5 1 , 252, 2 6 5 ; in direct proportion to intensity of emotion, 36, 37, 90, 9 1 , 96, 97 repository of, 2 3 , 24, 2 7 - 3 0 , 38, 77, 78, 106, 109, 1 1 5 - 2 2 ultimate seat of, 1 2 1 vividness of (recall), produced by faulty activity of association systems, 1 6 7 - 6 9 , 1 7 3 , 236, 2 3 7 ; and consequently by increased thalamic activity, 25, 26, 1 7 3 , 1 7 5 , 180, 204, 2 2 0 - 2 3 , 237, 262, 2 7 1 Mental attitude, 2 0 1 , 202 based on illusion, 148, 2 4 9 ; on delusion, 148 conditioned by bodily need, 202 effect of intermediary mimetic stimuli on, 203, 204, 2 1 4 , 2 1 5 persistence of, subject to L a w of Evolution and Dissolution, 203, 204 Mental confusion, 1 5 7 , 166, 1 7 4 , 1 7 7 , 178 Mental "cure," 2 1 4 Mental defectiveness and retardation, 25, 1 5 7 Mental functions, 6, 1 3 , 1 6 - 1 8 , 43, 261 development of, with experience, 247 in relation to orientation, 89, 2 1 5 , 2 1 6 ) to sensory reception, 1 7 , 1 8 , 1 5 5 , 1 5 6 , 1 5 8 69, 1 7 1 - 7 3 , 179, 180, 2 3 3 - 3 6 ; to training and heredity, 2 1 5 , 2 1 6 persistence of, under depressing conditions, 8, 1 3 - 1 7 , 1 2 1 , 1 2 2 , 204, 245, 246, 2 5 5 60, 262, 2 6 4 ; in relation to L a w of Evolution and Dissolution, 8, 1 3 - 1 6 , 1 2 1 , 1 2 2 , 204, 257, 259 seat of, 4 Mental index, 37, 1 8 8 , 1 9 2 , 202, 2 2 1 , 2 3 9 - 4 3 Metabolism, 6 1 ; in sleep, 225 Metaphor, 1 4 1 , 1 4 2 Meyer, Adolf, 1 2 8 , 1 6 5 , 169 Meyer's loop (See Optic radiation and Henschen's loop) Midbrain (or mesencephalon), 95, 229, 2 3 0 ; section of, 1 7 5 Migraine, 164, 169 Mill, John Stuart, 7, 9 Mimesis (See Imitation) Mind, 7 ; relation of, to body, 4, 6 Morphine, 258, 259 Morrison, J . Francis, 94, 1 0 1

28I

Motion, law of, t Motor systems, cerebral (See Nerve systems) Movement, 3, 8, 1 5 , 1 7 , 5 1 , 56, 78, 86, 1 4 J , 1 4 7 , 166, 224, 226, 250 as manifestation of emotion 26, 6 9 - 7 1 , 8a84. 93I 94> 96» > ° ° . >3«-39> >94, >95» 211 basic motives for, 1 8 3 , 185 clonic, 40, 94, 1 7 5 - 1 7 8 (See also Convulsions) ; in sleep, 226, 263 in learning, 195, 196, 200, 2 0 1 ; in normal epileptoid reaction, 1 7 9 ; in sleep, 43, 59, 226, 2 6 3 ; in states of attention ( F i g . 1 0 , P- ' 9 7 ) . i 9 í ~ * ° i » I I 7 - 1 9 » " 3 . i" thought, 2 1 8 , 2 1 9 in relation to feeling, 93, 94, 184, 1 9 2 ; to sensation, 14, 1 5 , 1 7 , 40-43, 69-74, 120, 184, 185, 192, 194-96, 2 0 1 , 2 1 1 , 2 1 7 1 9 ; to will, 1 0 5 - 7 , 226, 227 integrated pattern of, in epileptic seizure, 1

7S> >76 involuntary, 72, 73, 2 1 4 of digestive organs, during strong emotions, 3 1 - 3 4 . 54 productive of sound, 1 3 6 - 3 9 , 201 reflex, 57, 68, 69, 7 1 , 106, 107, 259 representative of mental attitude, 203 respiratory (See Respiration) skilled, of expression, 94, 1 1 7 , 1 1 8 , 120 "spontaneous," 1 4 1 startling or jerking, in sleep, 227, 244, 245, 252, 263 Müller, Carl, 224, 266 Multiple sclerosis, 95 Muscles, 6, 36, 45, 54, 60-62, 78, 92, 93, 99, ii4> 17•> ' 8 8 , 193 facial, 43 ; contractions of, 96, 120, 135 of internal organs, 30, 34, 35, 42, 49, 50, 52, 68 Muscles, skeletal, 23, 30-32, 34, 42, 56-58, 68, 96, 98, 2 1 3 antagonistic, 106, 1 2 5 ; "reciprocal innervation o f , " 51 contractions of, 68, 78, 79, 1 3 5 , 196, 198, 2 0 1 , 232, 234 control of, by cerebral cortex, 30, 48, 49, 85, 86, 103, 1 0 5 , 107, 157 coordinated into pattern of movement, 69 fatigue of, reduced by adrenin, 54, 65 flaccidity of, in terminal stage of epileptic seizure, 1 7 7 , 178, 180 in relation to autonomic system, 93, 96, 2 3 2 ; to cerebrospinal system, 49; to cir-

282

INDEX

Muscles, skeletal (Continued) dilatory system, 227, 228, 232, 2 3 } ; to respiratory system, 232, 233 in sleep (See Sleep) in states of attention (5«« Attention) plasticity of, in cataplexy, 230 relaxation of, 175, 209, 210, 221, 223, 224, 226,

rigidity

228,

234., 2 4 5 ,

o f , 83,

247,

257,

136, 137,

2j8,

14J, 218,

261

252j

caused by disability of cerebrocerebellar system, 175; in catatonic states, 192; in epileptic seizure, 6 7 , 1 7 5 — 7 9 ; in fourth stage of sleep, 252, 263; in normal epileptoid reaction, 83, 179; in Parkinsonian states, 192, 214; in states of attention, 217-20

tensions of, 201 Muscular activity, 53 as stimulus to mid-autonomic system, 53, 55, 56 in relation to adrenin, 54-, to emotions, 23, 3 2 . 34~3l, 55. 9 2 i to heartbeat, 52; to internal organs, 261 Myasthenia, 94 Myelination, 109 Myerson, Abraham, 55, 66 Mysticism and Mystics, 4, 212, 213, 247

olfactory, 70 sensory, 40, 48, 67, 90, 99 Nerve pathways and systems, 75.

79.

80,

118,

150,

« 7 .

»34.

262,

263,

83-85, 163,

»36, 265,

171, 245, 270,

92,

14, 95,

48-54,

i n ,

204,

207,

259,

260,

177-80, 250,

68,

105-8,

252,

27t

activity of cerebral motor, produced by diminished functioning ot association systems, 1 7 4 - 7 9 , 2 6 2 arcuate (See Association systems) association (See Association systems) auditory, effect of injury of, 161, 167 autonomic (See Autonomic systems) cerebral, 45, 77, 79, 84, 87, 89, 99, 177, 178, 181, 182, 245, 262, 263; course of, 46-48 cerebrospinal, corticobulbar and corticospinal (See Pyramidal tract) cerebrocerebellar, 175; activity of, extinguished before that of corticospinal, 175, 180; disability of, responsible for muscular rigidity, 175 corticothalamic (Fig. iG, p. 4 1 ) , 180 inferior longitudinal fasciculus (See Association systems) intercortical (See Association systems) modification of, by nerve impulses, 77, 80, 89

Neopallium, 70 Nerve impulses, 70,

77-79,

muscular and glandular, or efferent, 77, 40, 42, 46-50, 82-84,

87»

64, 65, 67,

«9i

9",

93.

68, 99.

106, 107, n o , 112, 161, 171, 175, 178, " 7 . 134» *45. 1J» course of, from receptor organ, 6, 78-81 effect of corticothalamic, 69, 74, 75, 79, 80, 83,

84,

89,

100

effects of nerve impulses traveling by long route, 8 2 - 8 5 ; by short route, 8 2 , 8 5 - 8 7 , «9 modification of, 70, 79, 83, 84; by changes in number and timing at synapse, 75, 77, 84, m , i i 2 ; by chemical changes at synapse, 75, i n , 271; by chemical state of the body, 75, 111 ; by effect of preceding impulses, 4 5 - 4 8 , 7 6 , 7 7 , 8 0 , 8 4 , 85» 8 9 , 9 0 , 9 9 , 1 2 5 , 1 8 2 , 2 0 2 ; by summation at synapse, i n ; general formula for modification of, in passage through cerebral cortex, 79, 80; in relation to number of receptors stimulated, 162; in relation to strength of stimulus, n o , i n of vision, 165, 167

221,

245,

253,

262,

264

of vision, 158, 162, 165, 166 receptive, or afferent, 76, 77, 220, 222, 123, 245,

256,

262,

264

sensory, 77, 161, 168, 172, 173, 220, 245, 247; injury of, in relation to orientation in present, 168; productive of simple hallucinations, 161, 168 striatal, 180 thalamocortical, 74, 76 theory of release of function of, 271 uncinate (See Association systems) Nerves autonomic motor, 49, 50, 53, 54, 57, 58 branching of, at entry into central nervous system (Fig. iA, p. 4 1 ) , 4 0 - 4 2 , 7«. 78 cerebrospinal motor, 49 conduction, 270; all-or-none principal of, n o ; along cerebral reflex arc, 125, 177, 178, 180, 220, 222, 250, 262; in nerve trunk, 48, 125 disability, wave of, 1 7 1 - 8 1 , 2 2 0 , 2 2 2 , 1 2 3 , 244,

245,

250,

262,

270,

271

INDEX Nerves ( C o n t i n u e d ) effect of severance of, connecting cortex and thalamus, 69, 70, 74; of vagus in dogs, 93. 9« intercalated, 57 optic, disease of, 162, 163; myelination of, 109

postganglionic, 4.9, j o , 54, J7 preganglionic, 49, 50, J4, 57, 58 refractory period of, 47 sensory, 5, 70, 1J7, 168, 169, 251 Nerve signaling, 1 0 9 - 1 2 Nitrous oxide, 14, 17, 256 Numbness, 15, 7], 160; in epileptic seizure, ' 7 i . 17 J

Opium, 1 8 7 , 2 4 0 , 2 5 6 / 2 5 8 , 2 5 9 Oedema, 57, 61 Optic atrophy, 163 Optic neuritis, 162 Orientation conditions for accuracy of, 89, 100, 156,

168,

182-85,

207,

208,

155,

216-18

in dreams, 238, 239 in past, 86, 88, 89, 100, 183, 185, 200, 205, 207-9, 261,

2 I I

>

2 ,

2,

5>

i

218,

234,

238,

283

218-21, 223; in emotion, 135, 136; in epileptic seizure, 175, 176; in sleep, 234, *47. »7«. 1 8 0 , 1 2 7 activity of, manifested by clonic movements, 1 75 as pathway of will, 8 7 , i o j - 8 effects of injuries to, in relation to will, 105-7. »57 interruption of, marked by sign of Babinski, 177,

180,

263

263

in present and immediate surroundings, 86, 88,

89,

200, 2

100,

207-9,

168, 2 I I _ I

3^> 2SS>

2

3 .

®2)

182, 2 I

2

5.

183,

185,

192,

2I
,

7°

Pain, 13, 15, 17, 25, 31, 55, S7, 91, 92, 114, 137,

'88)

193,

2

04,

219,

222,

258-60

Pallor, 61 Parable, 141 Parker, S., 101 Parkinsonian states, 192, 214 Parkman, Francis, 248, 269 Pavlov, J . P., 3 9 , 143-46, i5 2 > 2 0 9 > Périsson, 229, 268 Peristalsis, in strong emotion, 31-33 Pette, H., 265 Picrotoxin, 82 Piéron, Henri, 267 Pillsbury, W. B., 39, 90, 101, 223 Plato, 4, 8 Plutarch, 265 Pons, 161

Rage, 22, 25, 51, 52, 55, 81, 93, 97 Ranson, S. W., 230, 269 Raynaud's disease, 5 8 Reactions (or responses), 24, 25, 42, 62, 68, 83. 9°. I 2 « . 12 7> «38, i 4 2 ~ 4 7 . 149. «5°, 193. 194. 2 t o , 2 3 9 accompanied by autonomic activity, 6 3 - 6 6 , 99,

22

100,

147,

149

acquired, 188, 247 adaptation of, by learning, 81 appropriateness of, in relation to past experiences, 4 5 , 6 3 , 6 4 , 8 5 - 8 9 , 9 9 , 1 0 0 , 3

Posture, 78, 83, 109, 175, 209, 211 in attention ( F i g . 10, p. 197), 198, 199,

124,

125,

127-29,

196-99,

216

by movement, 2 6 , 3 0 , 3 8 , 6 9 - 7 1 , 8 2 , I 9 9 . i°°> ' 3 5 - 3 9 . 94~2oi, 211,

93-96, 217-19,

223

"conditioned" (See Stimuli, reactions t o ) emotional, 2 0 , 2 6 , 3 0 , 3 7 , 3 8 , 6 2 , 6 9 - 7 1 , 82-87, 99. 100; in absence of visceral and vascular activity, 9 3 - 9 7 ; in decorticated animals, 26, 28, 29, 43, 8 6 ; in lower animals, 2 6 - 2 8 ; intense and immediate, in disease of thalamus, 7 0 - 7 4 ; under action of Picrotoxin, 8 4 - 8 6

I N D E X

284

Reactions ( o r responses) (Continued) endocrine, 147 glandular, 86, 151, 239 in animals with rudimentary cerebrum, 69, S i ; in cerebrumless animals, 26-19, 38, 4 3 ; in decapitated frog, 42, 86; in decorticated animals, 86, 87 in dreams, 238, 239 in

relation

to bodily

need,

142-48, 150,

to feeling, 91, 9 2 ; t o imagery and hallucination, 207, 109, 220, 222 j t o sensation, 5, 40, 42, 91, 92, 182, 183» t o thought, 207, 208, 218, 220, 222 lack o f guidance by, productive o f defective cortical functioning, 180, 242; o f disorientation,

207—9,

220

of light ( v i s u a l ) , 4, 5, IJ, 24, 40, JI, 62, 73. 77. 7*. >09. " 4 .

I2

S.

IJ6> 160-62,

t o number of

182, 194, 206, 213, 218, 231, 232, 244,

nerves in cerebral cortex, 8 1 inherited, 188 mimetic ( S e e Imitation) n o r m a l epileptoid, 136, 137, 145, 179, 181 of escape, 1 3 9 ; of terror, 237 offensive and defensive, 97 permanence of effects o f , 130, 131 persistence o f , i n l e a r n i n g , 196-99 protective, in absence of sensation, 42, 43, 86

246; effects o f injuries of, 161; of pressure, 234; o f smell ( o l f a c t o r y ) , 5, 114, 125; o f sound ( a u d i t o r y ) , 4, 5, 40, 62, 71-73. 77. 7«. «3. 84, " 4 . i j « . 161; effects of injuries of, 1 6 1 ; of taste (gustat o r y ) . 5 . 40, 7 7 . i i 4 , « 2 5> 2°6, 218; o f touch ( t a c t i l e ) , 4, 40, 43, 77, 78, 114 Re-cognition

151,

startle,

188,

193-96,

82-84,

239;

I37> I4J. 1 7 9 .

181

to complex stimuli, 148, 1 5 1 5 to f e a r , 13644, 147; to feeding situation, 33, 143-47, 193, 209, 239; t o r e p r e s e n t a t i o n ,

12J-29,

131-42, 148-Ji. 184»

sym-

BOLS, 1 3 1 - j i ,

2

39>

2

49>

184, 239, 2 4 9

" u n c o n d i t i o n e d " ( S e e Stimuli, reactions t o ) vascular, 86, 93 visceral, 97, 143, 147 Reasoning, 8, 13, 15, 207, 216 correlation o f past memories, 207 loss o f , in disease of prefrontal region of cerebrum, 1 2 1 , 122 R e c a l l , 109, 114, 236, 239 in relation to hallucination, 157, 161, 167«9.

173-75

initiated b y relative inactivity of sensory reception, 2 3 5 , 236 mechanism o f , in redintegration, 149, 150 vividness o f , produced by diminished activity of association systems, 167-69, 1 7 3-7 J , 180,

235-37;

a n d b y consequently i n -

creased thalamic activity, 1 7 1 , 180 Receptors, sensory, 4, 46, 68, 69, 84, 86, 87, 89, 100, 109, i n , 171, 251 effects o f injuries to, 161-63, 168, 169 excitation o f , by symbols, 143-47 guidance by, in correlating memories, 196, 200, 206, 207, 217, 218, 220, 222, 245,

246; in learning, 196, 200; in orientation in present, 182, 200, 206-9, 217> 218

in relation to external disturbance, 68, 89;

a function o f cerebral cortex, 96, 98 in relation t o past experience, 88, 89, 96, 100

Recuperation, 233 Redintegration,

149-51

R e e d , C . I . , 225, 266 Reflexes, 57, 106, 252 abdominal, 7 1 chain, 147, IJI clonus ( S e e C l o n u s ) conditioned,

97,

142-47,

150, 151, 209

cutaneous, in sleep ( S e e S l e e p ) dependent on bodily need, 144-48, 150 dorsiflexion o f great toe (See Babinski, sign of) in epileptic convulsions, 175-77 in sleep (See S l e e p ) k n e e - j e r k , 68, 226; diminished b y training, 107; in relation to motor apparatus of cerebral cortex, 271 of autonomic system, 57, 59 propioceptive (See S l e e p ) s a l i v a r y , 209 unconditioned,

144-48

under action of d r u g s , 257-60 vestibular ( S e e S l e e p ) Representation, 151, 203, 205, 211, 212 as a basis o f art, 148-51; o f delusion, 148, 150, 151, 203, 249, 264, 265; o f illusion, 148,

150,

249, 264, 265

confusion o f likeness with identity i n , b y means o f comparisons, 141, 142, 249, 250, 264, 265

direct, 127, 128, 184; chances of e r r o r in, 105, 127, 128, 184, 185

INDEX Representation ( C o n t i n u e d ) evolution o f , i n t o symbolism, 1 3 2 - 4 2 , 1 4 9 , 150) in a r t , 1 4 9 ; in gesture l a n g u a g e , •35. '36> I * 1 i ' n government, 140, 1 4 1 , 1 4 9 ; in spoken l a n g u a g e , 1 3 6 - 4 2 , 1 4 9 1 in w r i t i n g ( F i g . 6, p. 1 3 3 ) , ( F i g . 7 , p . > 3 4 ) . ( F i g . 8, p . i 3 i ) . 13 I — 35» 1 4 1 > 149 in dreams, 2 3 S , 2 3 9 , 2 4 3 , 2 4 5 ; in i m a g e r y , i37 in relation to suggestion, 1 5 0 , 1 5 1 , 2 1 1 - 1 5 , 249 indirect, 1 2 8 , 1 8 4 ; chances of e r r o r in, 1 2 8 , 1 2 9 , 1 8 4 , 2 0 3 , 2 6 4 ; in a r t , 1 2 9 ; in e d u cation, 1 2 8 , 1 2 9 , 1 3 1 ; in g o v e r n m e n t , 129 influence o f , on w i l l , 105 significance o f , 1 2 4 - 2 7 ; in l o w e r organisms, 126, 127, 184 Respiration a n d Respiratory movements, 26, 78 in alcoholic intoxication, 8 ; in s t r o n g e m o tions, 35, S3 in relation t o gastro-intestinal disturbances, 2 2 5 ; to skeletal muscles, 53, 54, 2 2 7 , 228, 2 3 2 ; t o unconsciousness, 2 2 7 , 2 2 8 ; to somnolence, 225 respiratory system, 2 2 8 , 2 3 2 R h y m e , 248 R h y t h m , 248 R i t v o , M a x , 66 Rosenbach, O t t o m a r , 33, 226, 267 Rosett, J o s h u a , 1 0 1 , 1 1 2 , 1 5 1 , 1 5 2 , 163 (cases), 169, 1 7 0 , 1 7 2 ( c a s e ) , 1 8 1 , 2 2 3 , 269 Rousseau, J e a n Jacques, 2 1 6 Roussy, Gustav, 70, 1 0 1 R o w e , S. N . , 2 2 9 , 268 Rusby, H e n r y H . , 269 Sager, O., 2 2 9 , 2 3 0 , 268 Saliva (See Secretions) S a l m o n , A l b e r t o , 2 2 8 , 267 Sanz, J . , 2 3 0 , 268 Sasaki, K . , 39 Schoenberg, M a r k , 1 6 1 - 6 3 ( c a s e s ) , Schrottenbach, H e i n z , 33, 39 Schube, Purcell G., 6 6 Scopolamine (See H y o s c i n e ) Scotoma

169

scintillating, 1 6 1 - 6 4 , >66, 1 6 7 , 169, 172 zigzag, 162, 164 Secretion, 6 1 , 64, 96, 228, 2 3 3 , 2 6 1 a d r e n a l (See A d r e n a l m e d u l l a )

gastro-intestinal, 5 2 , 54, 1 4 7 1 d u r i n g s t r o n g emotions, 3 2 - 3 4 ; in sleep, 2 2 5 pancreatic, 61 p a r a t h y r o i d , 61 salivary, 33, 5 2 , 8 j , 1 4 7 , 193 thyroid, 61 Sensation, 4, 5, 44, 70, 111, 115, 1 2 0 , 1 2 1 , 190, 1 9 1 , 207 a f u n c t i o n of cerebral cortex, 29, 64, 77, 89, 90, 99, 1 0 0 a g u i d e to memories of past experience, 4 5 , 64, 206, 207 accompanied by corresponding emotion of v i t a l capacities a n d feelings, 90, 9 1 , 1 9 2 , 2 0 4 - 6 , 2 1 1 , 2 2 1 - 2 3 , 2 5 1 , 252 clarity a n d definiteness o f , 9 1 , 92, 9 8 - 1 0 0 , 1 1 3 , 1 8 2 , 2 0 4 - 2 0 6 ; dependent on spatial a n d temporal relations t o other subjective experiences, 1 1 3 , 1 1 4 , 1 2 5 , 1 4 1 ; a n d on internal and external conditions, 9 1 , 92, 1 1 4 , n $ ) « 3 0 - 4 1 ; in p r o p o r t i o n to correlation with past experiences ( m e m o r i e s ) , 89. 9 ° . 96, 98, 99, t 2 j , 1 J 5 , 1 J 6 , 169, 184, i 8 j , 1 9 3 - 2 0 1 , 204-6, a n , 215, 2 1 9 , 220, 2 2 2 , 2 7 0 ; to modification of nerve impulse, 1 8 2 , 1 8 3 ; to u r g e n c y of bodily need, 1 4 5 - 4 8 , 150, 156, 1 8 3 - 8 8 , 1 9 2 - 9 6 , 202, 205, 2 0 6 ; to strength of stimulus, 187, 188, 2 0 9 - 1 1 , 2 1 9 , 220, 222 definition o f , 88, 89 extinction of, u n d e r depressing conditions, 3 - 1 8 ; in relation t o L a w of E v o l u t i o n a n d Dissolution, 1 3 - 1 6 in disease of thalamus, 69, 7 1 - 7 4 in dreams, 224, 2 3 7 - 3 9 , *43> 0 1 hallucinations, 1 5 9 - 6 1 , 1 6 5 - 6 9 , 1 7 1 - 7 4 in onset of sleep, 2 2 6 , 246, 247, 259 in relation t o emotion, 19-21, 2 4 - 2 6 , 37, 4 0 - 6 6 , 90, 100, 1 9 2 , 2 0 3 - 5 ; t o feeling, 8 8 - 9 2 , 99, 1 0 0 ; to movement, 40—43, 6 8 - 7 4 , I 2 ° > I Z I > >84, 185, 1 9 2 , 1 9 4 - 9 6 , 200, 2 0 1 , 2 1 1 , 2 1 7 - 1 9 ; to receptor o r gans, 9 1 , 92, 2 1 0 i n t e g r a t i o n of, 4, 5, 1 3 ; in m e m o r y , 64, 167-69 loss o f , in relation t o protective

171,

285

reactions,

**» 43 " o b j e c t i v e " tests of, 113 of balance, 1 1 3 , 243, 2 4 6 ; of contact, 1 3 , i j , >7. 7 ° . 7 1 » 9*. ' 4 5 . 1 4 6 ; of gross vibration. 1 1 3 ; of hearing, 1 3 - 1 7 , »4. *5> 91» H 3 - I 5 > 131» 139-47» 15«.

286

INDEX

Sensation (Continued)

Sensory receptive areas (See Area* of cerebral

•J 8 > 239, 2 4 3 , 24.61 of pain (See Pain)}

cortex)

of position and movement, 1 4 , 1 5 , 1 7 , 4 3 ,

Sex-urge,

11 j ,

92,

166,

167,

24},

146,

of

247}

preaure, 92, 1 1 9 , 2 4 6 ; of smell, 9 1 , 148,

150,

158,

166,

167,

219,

taste, 9 1 , 1 1 3 ,

114,

219,

temperature,

91,

247 ; 113,

43> 7 0 ,

of

of

141,

71.

14,

115,

13:,

144,

167,

194,

200,

148,

156,

42,

71,

of

151,

158,

Simile,

74,

176,

243,

259;

Sjövall,

Einar,

24, 2 J , 40, 9 1 ,

113,

Sleep, 3

of

167,

219,

ijo,

148,

1J6,

228,

163,

o p e r a t i v e f o r production of m o v e m e n t ,

184,

by

211,

218,

209-14;

reasons f o r dominance o f certain ones,

183-

192,

194-96,

200,

201,

219;

and

posture,

209,

219

7 0 ; in disease o f thalamus, 156,

of

t71-73,

155,

i77-8°i

100,

182-85,

significance o f ,

r e l a t i o n o f , to emotions,

2 1 0 , 2 4 7 , 2 6 3 ; by s u g g e s t i o n , 2 1 1 ,

213-

222 231-33;

de-

terioration of l i v i n g m a c h i n e r y , 2 3 3 ;

reception,

ex-

40-66

mental

functions,

207-9,

218,

17,

220,

and

for

their

'S6>

159_i69>

'73>

234,

236-238, to

155,

222,

262;

ings,

231-33,

clonus in, 226,

disintegration

256,

218,

dreams

and

156;

115,

nerves,

209-14,

256,

262,

120,

17,

155,

excessive,

220,

222,

experimental

263;

disturbances, 156,

196, 200; past,

121,

207,

164,

157-69;

to

237, 169;

208,

218,

91, of

to

167-69;

234,

to

182-85, area

sensory

to

sleep,

238,

to t e m p o r a r y

163,

in

onset

of,

253,

functional to

thought,

220,

222,

2 3 3 - 3 6 , 262, 263

normal

sleep,

211-13,

217,

in sleep 262,

produced 263,

by

drugs,

265

228-30 production

of,

in

animals,

i m a g e r y in onset o f , 2 0 7 , 209, 2 1 1 - 1 3 , 234,

236,

237,

245,

252,

253,

222, 261-

65

in relation to autonomic nervous system, 69, 227,

232,

241

induced by d r u g s , 2 5 5 - 6 0 , 265 internal changes in, 5 1 , 224, 2 2 5 , muscular

manifestations

of,

43,

227 59,

223, 226, 227, 234, 2 4 5 , 252, 2 5 3 ,

220, 259,

260 nerve apparatus f o r r e g u l a t i o n of ( F i g . p. 2 2 8 ) ,

(Fig.

12, p.

229),

256-59

Sleep)

order of extinction of sensory reception p r o l o n g e d abstinence f r o m ,

11,

228-30

245-47

o r d e r of extinction o f , in sleep (See under action of d r u g s , 4 - 7 ,

in 209,

230

hallucination,

161—69;

162, 233,

memories

222, 224, 225, 2 2 7 , 2 3 4 , 2 3 7 - 4 5 , 2 4 8 - 5 5 , 265;

to sensory

158,

161,

265

i68> 2 0 7 ,

256-59,

263 ; to sensation, 40,

155,

192,

'55)

to l e a r n i n g ,

234,

receptors,

261

(hallucinations) '63I

157.

262-264

in present and

cerebrum, sensory

substances,

263

of

264,

171-73,

236,

vividness, 2°7>

imagery

239, 2 6 2 - 6 4 ; orientation 125,

energy-producing

256,

158,

234,

of

1 5 5 , 1 5 6 , 207, 209, 220, 222, 234, 2 3 6 -

207-10,

224,

245-50

111

diminution o f , a condition f o r initiation

92,

of

sleep,

232, 2 3 3 , 2 5 3 , 2 6 1 ; state o f the s u r r o u n d -

'S7i

relation

normal

tem by cerebral cortex i n , 2 4 1 , 262

42-45 19, 20, 37,

271

6>

192, 209,

defective control of a u t o n o m i c n e r v o u s sys-

a p p a r a t u s o f , 1 7 3 , 2 1 0 , 246, 2 5 3 , 263, 264,

in

attention,

o f , 249, 250, 264,

256-58

Sensory or i n f o r m a t i v e state, 5

Sensory

of

muscular

confusion of likeness w i t h identity in onset

200

under action of d r u g s , 14, 1 5 , biological

scope

by

haustion

present,

1 8 2 ; and in past, 89, 99, 192,

40-44,

71-74

orientation 169,

267

relaxation,

15,

narrowing

causes o f

204-6

relation o f , to causative disturbance, significant

229,

caused by mechanism o f i m i t a t i o n , 2 1 3 , 2 1 4 ;

243

185,

88,

266

267

a w a k e n i n g f r o m , 2 5 3 , 2 5 5 , 2 5 6 , 2 6 1 , 264

158,

232,

12J,

141

Simpson, G e o r g e E r i c , 2 2 5 , W.,

167;

265

181

Sinkler,

147,

" 3 .

1j,

247}

225,

Sherrington, C . S., J I , 66, 86, 93, 1 0 1 ,

touch,

146,

9«>

vision,

141,

113,

144

Shepard, John F., 1 2 4 ,

224

reflexes in, 226, 227, 2 5 2 , 2 5 3 , 2 6 3 , 264

in,

I N D E X Sleep ( C o n t i n u e d ) rhythm o f , 2 2 7 sleeplessness, 2 2 9 , 2 5 9 stages o f , 1 5 5 , 2 2 0 , 2 2 1 , 2 2 3 , 2 2 J - 2 7 , 2 3 3 , 234,

241,

245-248,

250,

25$,

162;

of

hallucination, 2 3 7 - 3 9 , 2 4 5 . 2 5 2 - 5 6 . 2 6 I 6 3 ; of imagery, 2 3 6 , 2 3 7 , 1 4 J , 2 5 2 , 2 5 3 , 261-63; motor manifestations, 2 4 4 , 2 4 5 , 2 5 2 , 2 J 3 , 2 5 6 , 2 6 3 , 2 6 4 ; of thought, »34-36. 2 4 5 . 2 5 2 . 2 5 3 . »62, 2 6 3 , 2 7 0 , 2 7 1 ; of unconsciousness and muscular flaccidity, 209, 2 5 3 , 256, 263 startle in (See Startle) Smart, W . A . M . , 2 6 9 Smiling, 9 5 , 1 3 J , 1 9 4 , 1 9 5 Soca, F., 2 2 9 , 2 6 7 Solis-Cohen, Solomon, 2 6 9 Sollmann, T o r a l d , 2 6 9 Somnolence in cataplexy, 2 3 0 ; in disorders of thalamus or hypothalamus, 2 2 8 - 2 3 0 ) in Parkinsonian states, 1 9 2 respiratory movements in, 2 2 j Sorrow, 6, 2 2 , 3 0 , 3 1 , 5 5 , 9 4 , 9 5 Soul, functions o f , 4 - 6 Saint T h o m a s ' Aquinas on, 5 seat of, 4 , 6 , 212 Spencer, Herbert, 7 - 9 , 1 4 8 , 1 5 2 Spiegel, E. A . , 2 3 0 , 268 Spinal cord ( F i g . i j , p. 4 1 ) , 4 0 , 4 2 , 50, j 6 , 5 7 . 78, 79. 86, 8 7 , 1 0 6 , 1 0 7 , 1 5 7 , 1 7 7 , " 7 . 2 4 5 . 2 57> 2 59> 2 6 0 , 2 6 4 , 2 7 1 severance o f , in dogs, in relation to expression of emotions, 9 3 , 9 8 ; in higher animals, 4 2 , 4 3 , 6 9 , 86 Startle, 82, 83, 1 3 6 , 1 3 7 , 1 4 5 , 1 7 9 , 1 8 1 in sleep, 2 4 4 , 2 4 J Stimulation, 5 4 , 1 0 7 ,

212,

219,

intermediary, 1 1 7 , 203, 2 1 3 , 2 1 4 ; in learni n g and acts of imitation, 195, 196, 200, 2 0 1 ; effect o f , 2 0 1 - 3 , l , J - , S internal, 239 of

contact, 9 2 ; of cold, 5 3 - 5 5 , 7», 146, 1 4 7 ; of d a n g e r , 187, 2 4 7 ; of gravitation, 1 0 9 ; of heat, 55, 7 1 ; of hunger, 1 4 4 - 4 7 , 150, 2 3 9 ; of light, 52, 65, 92, 144, 148, 150, 1 9 3 - 9 6 . 207, 2 1 8 ; of movement, 2 5 0 ; of odors, 52, 148, 150, 207, 2 1 8 ; of pain, 5J, 92, 207, 2 2 6 ; of position, 9 2 ; of sound, 52, 65, 82-85, 9 2 > i o 9 > ' 4 3 - 4 7 . i93-95> 2 °7> 2 ' ° > 2 »*> 2 5 ° i o i taste, 92, 1 4 8 ; of thirst, 144, 147, 1 S 3 85, 187 peripheral, 73 precedence

111,

226, 234,

222,

230

appraisal of, 1 3 6 , 1 3 7 effect of in disease of thalamus, 71—74.; on mid-autonomic, 5 3 , 57 in relation to bodily need, 1 4 4 - 4 7 , i j o . i j t , 1 8 3 - 8 7 . > 9 ' . »93-96. 2 0 2 > 2 3 9 i preceding stimuli, 1 2 5 ; to scope of consciousness, 1 8 4 - 8 8 ; to sleep, 209

taken

by

strong

stimuli,

187,

188, 207 proprioceptive, 200, 209 reaction ( o r response) to complex stimuli, 149, 1 5 0 ; to "conditioned" ( a c q u i r e d ) , 9 7 . 1 4 4 - 4 7 . »5°. " 5 1 . 2 °9> 2 I ° . 2 3 9 . to "neutral" (inherited), 144, 145; to strong stimuli, 187, 1 8 8 ; interrupting thought, 2 0 7 ; to "unconditioned" (inh e r i t e d ) , 1 4 4 - 4 8 , 150, 151 representative or symbolic, 1 4 2 - 4 7 , 150, 184, 186, 193, 195, 2 5 0 ; suggestive, 2 1 1 2 I 5 > 2 39> 2 4 7 relation of "conditioned" to "unconditioned," 1 4 5 - 4 8 , 150, 1 5 1 ; in the laboratory, 1 4 5 - 4 7 , 150, 1 5 1 ; in real life, 146, 1 4 7 ; in man, 146, 1 4 7 ; in higher animals, 146, 147, 150, 151 rhythmic repetition of, 210 Stomach, 6, 9 1 , 92

activity 110,

2S7-59. 2«3 of mid-autonomic, J7, j 8 of nerve trunk, 1 1 0 plantar, 2 2 6 , 2 5 2 , 2 6 3 threshold o f , 991 in disease of thalamus, 7 1 , 72 Stimulus, 3 3 , 9 9 , 1 0 6 , 1 1 0 , 1 2 2 , 2 0 1 , 2 0 2 ,

2IT,

287

of,

during

strong

emotions,

32-

34 contractions o f , in sleep, 1 2 5 innervated by autonomic system, 52 Stramonium, 256 Stratton, G . M . , 9 Striatal system ( S e e Nerve systems) Strychnine, 96 Suggestion, 150, 1 5 1 , 2 1 1 - 1 5 , 222, 2 4 9 ; conditions f o r effectiveness o f , 2 1 1 Sweating, 54, 5 5 , 58, 6 1 , 97 S w e l l i n g , 5 7 , 73, 159, 165 Symbol, 1 3 1 , 132, 138-42, 144, 145, 1 4 9 - 5 1 , 184, 195, 196, 203, 2 i i , 239, 249, 250 (See also Symbolism) effectiveness of same symbol in evoking different reactions, 147

288

INDEX

Symbolism a means of conserving energy and time, 131, 150, 264; for responding to a complex situation as a whole, 1 3 1 , 132 as a basis of art, 148-5 ij of delusion, 148, 150, 151, 214, 2ij, 249, 264, 265; of illusion, 148, 149, 249, 264, 265 biological causes of, 124-27, 184 "conditioned" reflexes in relation to (See Reflexes) confusion of likeness with identity in, 148, 249, 250, 264, 265; by means of comparisons, 141, 142, 249 evolved from representation, 132—42, 148, 149, 264, 265; in art, 148, 149, 151; in gesture language, 13J, 136, 141; in government, 140, 141, 149} in spoken langauge, 136-42, 149; interjections representative of emotion (See Interjections) ; in writing ( F i g . 6, p. 133), ( F i g . 7, p. 1 3 4 ) , ( F i g . 8, p. 13$), » 3 » - J 5 i ' 4 1 . »49 influence of, on will, 105 main conditions f o r effectiveness o f , 143, 144

response to symbolic stimuli, 142-47 Symmetry, 248 Sympathetic system (See Mid-autonomic system) Sympathin, 55, 1 1 1 Synapse ( F i g . i C , p. 41), 46-48, 75, 76, 111 Szymanski, J . S., 227, 267 Thalamus ( F i g . i C , p. 41), ( F i g . 12, p. 229), 48, 65, 68-70, 76, 78, 89, 95, 98, 103, 171,

204,

222,

228, 261

activity of, in direct proportion to diminished cortical activity, 24-28, 173, 175, 180, 204, 220, 221, 223, 237, 262, 271

as coordinator of vital activities with those of cerebral cortex, 68, 69, 89 case histories of disease of, 71-74 different effects on, of nerve impulses traveling by short and long route, 82-86, 89 disorders of, in relation to autonomic functions, 69, 70; to following responses, 6974, 204; to intensity of feeling, 69-74, 204, 205; to sensation, 69-74, 98, 99; to threshold of stimulation, 7 1 - 7 4 ; to vividness of recall, 17J, 180, 204, 20j, 220, 221, 223

effect of corticothalamic impulses on, 75, 79, 80, 83, 84, 89, 100

emotional mechanisms of, 69, 70, 7 4 , 79, 89, 221, 271

external geniculate body, 158 functions of, 90, 96, 98, too, 220, 221, 223, 262, 263; controlled by cerebral c o r t e x , 74-80, 82-84, 89, 98, 99, 103; i n

relation to conscious state, 70, 71, 74, 223 in relation to sleep, 228-30 mechanism of, 80, 83, 84, 99, 220, 222, 223, 227, 256, 262

thalamic syndrome, 7 1 , 72 the seat of feeling, 89, 90, 96, 98, 100, 220, 221, 223

Theophrastus, 4, 9 T h i r s t , 62, 91, 144, 147, 183-85, 187, 241

Thomas Aquinas, Saint, 5 Thought, 13, 14, 19, 117, 118, 127, 130, 241, 2 J7> 2 5 9 a function of association systems, 222, 223, 2

35> 1 3 6 . 2 4J> 163» * 7 i activity o f , conditioned by diminished activity of receptive apparatus, 6, 155, 156, 158, 207-9,

222, 233-36, 263

as mental index of a corresponding state of the body, 240, 242 definition of, 155, 156, 222, 262, 270 in relation to first stage of sleep, 234-36, 2 45> 2 5 2 > 2 53> 1 6 1 , 263» 2 7°> 2 7 ' i to m e m o r y , 207-9,

2I

&>

222

>

22

3> 2*>2> 270}

to orientation in present and past, 207-9, 215, 216, 218, 234, 263, 270; to structure of cerebrum, 157, 168 ; to training and heredity, 2 1 5 - 2 1 7 mechanism of, 168, 270 merging into imagery and hallucination, 20

7-9>

2I
> 220-22}

i n onset

20

o f sleep,

7> 2 3S> 2 3 6 most accurate and least vivid of mental functions, 155, 162, 270 rapidity of, 250, 251 reason for recurrence of certain thoughts at certain times, 239, 240, 242 relative immobility of musculature in activity of, 218, 219 seat of, 4 subjective reexperience of sensations in, 252, 270

Thromboangiitis obliterans, 58 Tilney, Frederick, 94, 101, 112 Tingling, 57, 72, 73, 171, 173 Tinnitus, 161 Tobacco, 163, 187, 240 Tonus, 96, 177, 220, 263

INDEX Training, 88 in relation to imagery and hallucination, 216, 2i7) t o judgment, 215, 2 1 6 ; to mental attitude, 249, 252; to reasoning, 215, 216} to thought, 207, 215, 216; to will, 107 Trembling, 53, 93, 97, 147, 179 Tromner, E., 265 Tuber cinereum, 230 Tuttle, W. W., 266, 267 Tylor, Edward B., 137, 138, 151 Uncinate gyrus (Fig. j , p. 1 1 9 ) , 165 Valentini, Michaelis Bernhardt, 215, 223 Vegetative functions, substitution of, by cerebral functions, 188-90 Veitch, John, 9 Vernier, L., 229, 267 Viscera, 68, 93, 172 innervation of, by different divisions of autonomic system, 51, 54 Visions, 163, 2 1 2 , 252, 254, 255, 259 (See alto Dreams, Hallucinations) Volition (See Will) Washeim, Henry, 225, 266 Water, 62, 69, 91, 183-85, 187, 188, 193 Webster, Thomas Arthur, 225, 266

289

Weed, L. H „ 181 Weeping, pathologic, 93-9J Weichmann, Ernst, 244, 265 Weisenburg, Theodore, 1 1 7 , 123, 228, 167 Weiss, Morris M., 224, 265 White, Hale W., 269 Wigglesworth, V. B., 22J, 266 Wilcox, Reynold W., 269 Will a function of the cerebral cortex, 108 defect of cerebral cortex in relation to, 107, 1 J7 free, 103 non-volitional acts, 87, 103, 104 pyramidal tract as pathway of, 105-8 j effect of injuries to, 105-7, 157 reflexes in relation to, 106; patellar, 107 seat of, 4 volitional acts, 87, 103-5, 2 1 1 ; definition of, 105; difficulty a condition of, 104, 108} genesis of, 104, 105; in higher animals, 105; in relation to memory, 104-8} motive for, 104, 105, 107; negative, 103-5, 1 0 8 > positive, 103-5, 1 Wilson, S. A. Kinnier, 94, 1 0 1 , 2 5 1 , 269 Wood, Casey A., 170 Woodrow, C. E., 225, 266 Wundt, 182

Yawning, 194, 195