We have now presented some of the reasons based largely on gross animal behavior why fear is to be regarded as a response to phylogenetic a.s.sociation with physical danger. In further support of this hypothesis, I shall now present some clinical and experimental evidence.

Although there is not convincing proof, yet there is evidence that the effect of the stimulus of fear upon the body when unaccompanied by physical activity is more injurious than is an actual physical contest which results in fatigue without gross physical injury.

It is well known that the soldier who, while under fire, waits in vain for orders to charge, suffers more than the soldier who flings himself into the fray; and that a wild animal endeavoring to avoid capture suffers less than one cowering in captivity.

An unexpressed smouldering emotion is measurably relieved by action.

It is probable that the various energizing substances needed in physical combat, such as the secretions of the thyroid, the adrenals (Cannon), etc., may cause physical injury to the body when they are not consumed by action (Fig. 22).

That the brain is definitely influenced--damaged even-- by fear has been proved by the following experiments: Rabbits were frightened by a dog but were neither injured nor chased.

After various periods of time the animals were killed and their brain-cells compared with the brain-cells of normal animals-- wide-spread changes were seen (Fig. 13). The princ.i.p.al clinical phenomena expressed by the rabbit were rapid heart, accelerated respiration, prostration, tremors, and a rise in temperature. The dog showed similar phenomena, excepting that, instead of such muscular relaxation as was shown by the rabbit, it exhibited aggressive muscular action.

Both the dog and the rabbit were exhausted but, although the dog exerted himself actively and the rabbit remained physically pa.s.sive, the rabbit was much more exhausted.

Further observations were made upon the brain of a fox which had been chased for two hours by members of a hunt club, and had been finally overtaken by the hounds and killed.

Most of the brain-cells of this fox, as compared with those of a normal fox, showed extensive physical changes (Fig. 4).

The next line of evidence is offered with some reservation, but it has seemed to me to be more than mere idle speculation.

It relates to the phenomena of one of the most interesting diseases in the entire category of human ailments--I refer to exophthalmic goiter, or Graves' disease, a disease primarily involving the emotions.

This disease is frequently the direct sequence of severe mental shock or of a long and intensely worrying strain.

The following case is typical: A broker was in his usual health up to the panic of 1907; during this panic his fortune and that of others were for almost a year in jeopardy, failure finally occurring.

During this heavy strain he became increasingly nervous and by imperceptible degrees there developed a pulsating enlargement of the thyroid gland, an increased prominence of the eyes, marked increase in perspiration--profuse sweating even--palpitation of the heart, increased respiration with frequent sighing, increase in blood-pressure; there were tremor of many muscles, rapid loss of weight and strength, frequent gastro-intestinal disturbances, loss of normal control of his emotions, and marked impairment of his mental faculties.

He was as completely broken in health as in fortune.

These phenomena resembled closely those of fear and followed in the wake of a strain which was due to fear.

In young women exophthalmic goiter often follows in the wake of a disappointment in love; in women, too, it frequently follows the illnesses of children or parents during which they have had to endure the double strain of worry and of constant care.

Since such strains usually fall most heavily upon women, they are the most frequent victims of this disease. Now, whatever the exciting cause of exophthalmic goiter, whether it be unusual business worry, disappointment in love, a tragedy, or the illness of a loved one, the symptoms are alike and closely resemble the phenomena of one of the great primitive emotions. How could disappointment in love play a role in the causation of Graves' disease? If the hypothesis which has been presented as an explanation of the genesis and the phenomena of fear be correct, then that hypothesis explains also the emotion of love. If fear be a phylogenetic physical defense or escape which does not result in muscular action, then love is a phylogenetic conjugation without physical action.

The quickened pulse, the leaping heart, the accelerated respiration, the sighing, the glowing eye, the crimson cheek, and many other phenomena are merely phylogenetic recapitulations of ancestral acts.

The thyroid gland is believed to partic.i.p.ate in such physical activities.

Hence it may well follow that the disappointed maiden who is intensely integrated for a youth will, at every thought of him, be subjected by phylogenetic a.s.sociation to a specific stimulation a.n.a.logous to that which attended the ancestral consummation. Moreover, a happy marriage has many times been followed by a cure of the exophthalmic goiter which appeared in the wake of such an experience.

The victims of Graves' disease present a counterpart of emotional exhaustion. That the emotions in Graves' disease are abnormally acute is ill.u.s.trated by my personal observation of the death of a subject of this disease from fear alone.

Whatever the exciting cause of this disease, the symptoms are the same; just as in fear, the phenomena are the same whatever the exciting cause.

Figures 12 and 16 show the resemblance between the outward appearances of a patient with Graves' disease and of a person obsessed by fear.

Fear and Graves' disease have the following phenomena in common: Increased heart-beat, increased respiration, rising temperature, muscular tremors, protruding eyes, loss in weight; Cannon has found an increased amount of adrenalin in the blood in fear and Frankel in Graves' disease; increased blood-pressure; muscular weakness; digestive disturbances; impaired nervous control; hypersusceptibility to stimuli; in protracted intense fear the brain-cells show marked physical changes, and in Graves' disease a.n.a.logous changes are seen (Figs. 13 C and 15). In Graves' disease there seems to be a composite picture of an intense expression of the great primitive emotions.

If Graves' disease be a disease of the great primitive emotions, or rather of the whole motor mechanism, how is the constant flow of stimulation of this complicated mechanism supplied? It would seem that there must be secreted in excessive amount some substance that activates the motor mechanism. The nervous system in Graves'

disease is hypersusceptible to stimuli and to thyroid extract.

It might follow that even a normal amount of thyroid secretion would lead to excessive stimulation of the hypersusceptible motor mechanism.

This condition of excessive motor activity and hyperexcitability may endure for years. What is the source of this pathologic excitation?

The following facts may give a clue. In suitable cases of Graves'

disease, if the thyroid secretion is sufficiently diminished by a removal of a part of the gland or by interrupting the nerve and the blood supply, the phenomena of the disease are diminished immediately, and in favorable cases the patient is restored to approximately the normal condition.

The heart action slows, the respiratory rate falls, the restlessness diminishes, digestive disturbances disappear, tremors decrease, there is a rapid increase in the body weight, and the patient gradually resumes his normal state. On the other hand, if for a period of time extract of the thyroid gland is administered to a normal individual in excessive dosage, there will develop nervousness, palpitation of the heart, sweating, loss of weight, slight protrusion of the eyes, indigestion; in short, most of the phenomena of Graves'

disease and of the strong emotions will be produced artificially (Figs. 15 and 23). When the administration of the thyroid extract is discontinued, these phenomena may disappear. On the other hand, when there is too little or no thyroid gland, the individual becomes dull, stupid, and emotionless, though he may be irritable; while if a sufficient amount of thyroid extract be given to such a patient he may be brought back to his normal condition.

Hence we see that the phenomena of the emotions may within certain limits be increased, diminished, or abolished by increasing, diminishing, or totally excluding the secretion of the thyroid gland.

Graves' disease may be increased by giving thyroid extract and by fear.

It may be diminished by removing a part of the gland, or by interrupting the blood and nerve supply, or by complete rest.

In addition, at some stage of Graves' disease there is an increase in the size and in the number of the secreting cells.

These facts regarding the normal and the pathologic supply of thyroid secretion point to this gland as one of the sources of the energizing substance or substances, by means of which the motor phenomena of animals are executed and their emotions expressed.

Anger is similar to fear in origin and, like fear, is an integration and stimulation of the motor mechanism and its accessories.

Animals which have no natural weapons for attack experience neither fear nor anger, while the animals which have weapons for attack express anger princ.i.p.ally by energizing the muscles used in attack.

Although, as has already been stated, the efficiency of the hands of man has largely supplanted the use of the teeth, he still shows his teeth in anger and so gives support to the theory that this emotion is of remote ancestral origin and proves the great persistence of phylogenetic a.s.sociation. On this conception we can understand why it is that a patient consumed by worry--which to me signifies interrupted stimulation, a state of alternation between hope and fear--suffers so many bodily impairments and diseases even.

This hypothesis explains the slow dying of animals in captivity.

It explains the grave digestive and metabolic disturbances which appear under any nerve strain, especially under the strain of fear, and the great benefits of confidence and hope; it explains the nervousness, loss of weight, indigestion--in short, the comprehensive physical changes that are wrought by fear and by s.e.xual love and hate.

On this hypothesis we can understand the physical influence of one individual over the body and personality of another; and of the infinite factors in environment that, through phylogenetic a.s.sociation, play a role in the functions of many of our organs.

It is because under the uncompromising law of survival of the fittest we were evolved as motor beings that we do not possess any organs or faculties which have not served our progenitors in accomplishing their survival in the relentless struggle of organic forms with one another.

We are now, as we were then, essentially motor beings, and the only way in which we can meet the dangers in our environment is by a motor response.

Such a motor response implies the integration of our entire being for action, this integration involving the activity of certain glands, such as the adrenals (Cannon), the thyroid, the liver, etc., which throw into the blood-stream substances which help to form energy, but which, if no muscular action ensues, are harmful elements in the blood.

While this motor preparation is going on, the entire digestive tract is inhibited. It thus becomes clear why an emotion is more harmful than action.

Any agency that can sufficiently inspire faith,--dispel worry,-- whether that agency be mystical, human, or divine, will at once stop the body-wide stimulations and inhibitions which cause lesions which are as truly physical as is a fracture.

The striking benefits of good luck, success, and happiness; of a change of scene; of hunting and fishing; of optimistic and helpful friends, are at once explained by this hypothesis.

One can also understand the difference between the broken body and spirits of an animal in captivity and its buoyant return to its normal condition when freed.

But time will not permit me to follow this tempting lead, which has been introduced for another purpose--the proposal of a remedy.

Worries either are or are not groundless. Of those that have a basis, many are exaggerated. It has occurred to me to utilize as an antidote an appeal to the same great law that originally excited the instinctive involuntary reaction known as fear-- the law of self-preservation.

I have found that if an intelligent patient who is suffering from fear can be made to see so plainly as to become firmly convinced that his brain, his various organs, indeed his whole being, could be physically damaged by fear, that this same instinct of self-preservation will, to the extent of his conviction, banish fear.

It is hurling a threatened active militant danger, whose injurious influences are both certain and known, against an uncertain, perhaps a fancied, one. In other words, fear itself is an injury which when recognized is instinctively avoided. In a similar manner anger may be softened or banished by an appeal to the stronger self-preserving instinct aroused by the fear of physical damage, such as the physical injury of brain-cells. This playing of one primitive instinct against another is comparable to the effect produced upon two men who are quarreling when a more powerful enemy of both comes threateningly on the scene.

The acute fear of a surgical operation may be banished by the use of certain drugs that depress the a.s.sociational power of the brain and so minimize the effect of the preparations that usually inspire fear.

If, in addition, the entire field of operation is blocked by local anesthesia so that the a.s.sociational centers are not awakened, the patient will pa.s.s through the operation unscathed.

The phylogenetic origin of fear is injury, hence injury and fear cause the same phenomena. In their quality and in their phenomena psychic shock and traumatic shock are the same. The perception of danger by the special senses in the sound of the opening gun of a battle, or in the sight of a venomous snake, is phylogenetically the same and causes the same effects upon the entire body as an operation under anesthesia or a physical combat in that each drives the motor mechanism.

The use of local anesthetics in the operative field prevents nerve-currents from the seat of injury from reaching the brain and there integrating the entire body for a self-defensive struggle. The result, even though a part of the brain is asleep and the muscles paralyzed, is the same as that produced by the interception of the terrifying sound of the gun, or of the sight of the dangerous reptile, since the stimulation of the motor mechanism is prevented.

By both the positive and the negative evidence we are forced to believe that the emotions are primitive instinctive reactions which represent ancestral acts; and that they therefore utilize the complicated motor mechanism which has been developed by the forces of evolution as that best adapted to fit the individual for his struggle with his environment or for procreation.

The mechanism by which the motor acts are performed and the mechanism by which the emotions are expressed are one and the same.

These acts in their infinite complexity are suggested by a.s.sociation-- phylogenetic a.s.sociation. When our progenitors came in contact with any exciting element in their environment, action ensued then and there. There was much action--little restraint or emotion.

Civilized man is really in auto-captivity. He is subjected to innumerable stimulations, but custom and convention frequently prevent physical action. When these stimulations are sufficiently strong but no action ensues, the reaction const.i.tutes an emotion.

A phylogenetic fight is anger; a phylogenetic flight is fear; a phylogenetic copulation is s.e.xual love, and so one finds in this conception an underlying principle which may be the key to an understanding of the emotions and of certain diseases.

PAIN, LAUGHTER, AND CRYING[*]

[*] Address delivered before the John Ashhurst, Jr.. Surgical Society of the University of Pennsylvania, May 3, 1912.

PAIN

Pain, like other phenomena, was probably evolved for a particular purpose-- surely for the good of the individual; like fear and worry, it frequently is injurious. What then may be its purpose?

We postulate that pain is one of the phenomena which result from a stimulation to motor action. When a barefoot boy steps on a sharp stone it is important that the injuring contact be released as quickly as possible; and therefore physical injury pain results and impels the required action. Anemia of the soft parts at the points of pressure results from prolonged sitting or lying in one position, and as a result pain compels a muscular action that shifts the damaging pressure--this is the pain of anemia; when the rays of the blazing sun shine directly upon the retina, pain immediately causes a protective muscular action--the lid is closed, the head turns away--this is light pain; when standing too close to a blazing fire the excessive heat causes a pain which results in the protective muscular action of moving away--this is heat pain; when the urinary bladder is acutely overdistended the resultant pain induces voluntary as well as involuntary muscular contraction-- this is evacuation pain; a.s.sociated with defecation is a characteristic warning pain, and an active pain which induces the required muscular action--this, like the pain accompanying micturition, is an evacuation pain; in obstruction of the urinary pa.s.sages and of the large and the small intestine the pain is exaggerated, as is the accompanying muscular contraction--this is a pathologic evacuation pain; when the fetus reaches full term and labor is to begin, it is heralded by pain which is a.s.sociated with rhythmic contractions of the uterine muscle; later, many other muscles take part in the birth and pain is a.s.sociated with all these muscular contractions--these are labor pains; when a foreign body, be it ever so small, falls upon the conjunctiva or cornea there results what is perhaps the acutest pain known, and quick and active muscular action follows--this is special contact pain. Special pain receptors are placed in certain parts of the nose, the pharynx, and the larynx, the stimulation of which causes special motor acts, such as sneezing, hawking, coughing. Curiously vague pains are a.s.sociated with the protective motor act of vomiting and with the s.e.xual motor acts--these may be termed nausea pains and pleasure pains.

We now see, therefore, that against the injurious physical contacts of environment, against heat and cold, against damaging sunlight, against local anemia when resting or sleeping, the body is protected by virtue of the muscular action which results from pain.

Then, too, for the emptying of the pregnant uterus, for the evacuation of the intestine and of the urinary bladder as normal acts, and for the overcoming of obstructions in these tracts, pain compels the required muscular actions, For pa.s.sing gall-stones and urinary calculi, urgent motor stimuli are awakened by pain.

For each of these diversified pains the consequent muscular action is specific in type, distribution, and intensity. This statement is so commonplace that we are apt to miss the significance and the wonder of it. It is probable that every nerve-ending in the skin and every type of stimulation represents a separate motor pattern, the adequate stimulation of which causes always the same response.