It is impossible to review here in detail all the facts accumulated concerning the influence of the internal secretions upon all the processes of mind, intellectual and emotional. A volume would not suffice for their adequate consideration. Reflexes, instincts, habits, tendencies and emotions are involved in their machinery. The development and normal functioning of the intellect, the pure reason as Kant called it, are controlled by them. Brain, without them in solution, without enough of them in that wonderful solution, the blood, sleeps or remains dormant like the butterfly in the cocoon. The cretin, who has not enough thyroid or no thyroid, is an imbecile because of his deficiency. Supply him with thyroid from outside sources, feed him animal thyroid, be it of the sheep, the pig, or the goat, and behold a miracle! he is restored to the level of at least the relatively normal intelligence.

Acuteness of perception, memory, logical thought, imagination, conception, emotional expression or inhibition and the entire content of consciousness are influenced by the internal secretions. The most ultramicroscopic activities of the molecules and atoms in the highest nerve cells and nerve tissues are dominated. The speed of their chemistry and their associations, and thus the speed of thought, are regulated. Iodine has been shown to increase the electric conductivity of the brain that is, the rate at which electrons will fly through it. The thyroid may then be regarded as manipulating the amount of iodine brought to play upon the brain cells at a particular moment of danger or exaltation. Adrenalin increases the electric conductivity of the brain. Nerve impulses, and with them sensations and ideas, travel faster or flow more quickly through iodinized or adrenalinized brain cells. In dangerous situations we think more rapidly and keenly, for in emergencies the blood floods the brain with extra thyroid and adrenal secretions.

THE BODY-MIND COMPLEX

Mind, still regarded by most of mankind as something distinct and apart from the body, is thus exhibited as but part and parcel of it. A deaf, dumb, and blind animal, deprived of tongue, and olfactory mucous membrane, without sensations from the outside world can grow no mind, in the sense of intelligence. The sense organs of the body mediate the primary mind stuff. Without internal secretions and a vegetative system there could be no soul, in the sense of complex emotion. Nor those combinations of thought and emotion which synthesize attitudes, sentiments and character. The internal secretions and the vegetative system mediate the primary soul stuff. Mind is thus emulsified with body as a matter of cold literal fact. The soul was once a subtlety of metaphysics. Now when mind appears soaked in matter saturated with chemicals like the hormones, therefore woven out of material threads, the independent entity created out of intangible spirit flies like a ghost at dawn.

View the outlook. Mind, the slippery phantom, now becomes controllable for the purposes of everyday life, because we can put our fingers upon, touch, handle and change these material factors, the internal secretions and the vegetative system. Through them we may affect the very quality of the nerve tissue. The future of the race, the future of human nature, depends upon the knowledge to be born of the researches into the vast possibilities of this idea. Man, the Adventurer, the prey of Chance and Luck, will then become, indeed now becomes, the Captain of Fate and Destiny.

It is, of itself, a revolution in the intellect, to conceive of instincts and emotions, suggestibility and contra-suggestibility, initiative and imitation, volitions and inhibitions as chemical matters. In all their relations, mutually reacting effects and defects, excesses and deficiencies, the internal secretions set up psychic echoes and reflections. When morbid and their equilibrium dislocated, we may even have phobias and neuroses.

A man's nature is essentially his endocrine nature. Primarily, when he is born, he represents a particular inherited combination of different glands of internal secretion. They, constituting the inventory of his vital stock in trade, start him in life. Afterwards, food, the routine of his existence, the accidents of experience, education, disease and misfortune, in short, environment, modify him because they modify his ductless glands and his vegetative apparatus, as well as his brain, depressing some parts, and stimulating others, and so rearranging the system. In particular will he be transformed as the gland is affected which is the centre of the system to which the others adapt and accommodate themselves. The inertia of the system is very great, almost absolute, and always tends to return. If he has children, he hands on his constellation of endocrines, in spite of mishaps, not at all or only slightly transformed. Sometimes, however, the experiential transformation has been sufficiently deep, and shaken the very constitution of his germ-plasm. So family dispositions and traits, national and racial temperaments, are propagated, maintained and varied.

THE SEX INSTINCTS

Hormone reactions, as we have seen, initiate the complicated forces, processes and expressions of sex. The dictum of the founder of modern pathology, Virchow, that Woman was in effect an appendix to the ovaries, has long been taken to apply to her psychic traits as well as somatic. Her mind, like her skin, her hair and her pelvis, is a product of the ovarian endocrines. But these determinations are by no means her monopoly. Man is likewise a creation of the chemical wheels within wheels and springs within springs that are his glands of internal secretion. That he is not so obviously an appendix to his testes is due to two reasons. First, the male sex hormones have not the instability nor cyclic rhythmicity of the female. Secondly, and perhaps consequently, his sex instincts have become overlayered with other more labile instincts, with habits and customs and necessities that appear to oust the sex instinct into an altogether decentralized position. Moreover, it is the function of the female to be the excitor in the sex process: her subconscious, thoroughly aware of the fact, sees to it that the sex instinct stands starkly central and dominating in her life.

The moods of love, like the more stereotyped manifestations of sex, are dependent upon a proper supply to the blood of the internal secretions of the reproductive organs, the gonadal endocrines. If the testes are removed from frogs, it is found that the clasp-reflex, symptom of sex desire, is abolished. If, after an interval of several days, the testes' extract is injected into the frog, the reflex reappears for a few days. The hormone provoking this sex reflex is present in the testes only during the breeding season. In birds, the seasonal nesting and migrating instincts may be eliminated by interfering with their ovaries. At the same tine there is a change in their plumage toward the male type. Similarly, the males, when their sex endocrines are cut off, will change their psychic nature as well as physically. Besides owning his flag-waving comb, his spurs and brighter feathers, the rooster struts to attract the female, and fights aggressively with his sex competitors. When he is made a capon, he loses his spurs and comb and distinctive plumage, and in addition becomes retiring and submissive, in short, a pseudo-hen in his instincts as well as in appearance. If the genital glands are extirpated from a male before puberty, the wattles remain small, pale and bloodless, no active, amorous or combative instinct emerges. The creature maintains a demure silence, and may even be sought by a virile male. So we may see homosexuality of a kind in the lowest animals. On the other hand, hens deprived of ovaries tend to metamorphose in the male direction, even to acquire the male spurs, and to display the male attitudes.

All through the animal world, in the springtime, when the pituitary awakens or increases its secretion, and so stimulates the sex glands to augmented activity, emotions of sex and their expression are provoked by the inner stirring. When the nightingale warbles passionately and the mocking bird gurgles provokingly, when the robin fills its scarlet breast and the starling floats in ecstasy through the perfumed air, when the pigeon coyly woos its mate, and the butterfly flirts with the dazzling multicolors of its wings, when all the marvelous devices of sex attraction in nature, selection and courting, mating and reproducing are pondered, who but must wonder at the infinite possibilities of reaction of the sex hormones? All is for love, and all is because of the love in the blood that is manufactured unconsciously by a few hidden cells.

EXPRESSIONISM AND EXHIBITIONISM

We need a detailed examination of the various forms of expression art has differentiated into, in its relation to exhibitionism and as effects of the circulating libido-producing substance of the gonads. Sex exhibition differs in man and woman because of the differently combined internal secretions that are their substrates. The male's attitude, aggressive pursuit, is instigated by the compound adrenal and gonad endocrines. The female's various emulsions of coyness and display are motivated by posterior pituitary and gonad hormones in alliance.

It is a dogma to state that the internal secretions of sex do not begin to function until after puberty. Some children manifest exhibitionism with a certain independence of environment. Before adolescence a good many girls act like tom-boys, and are distinguishable externally from boys only by their clothes. But others display signs of sex differentiation that are to be traced back to an awakening interstitial gonad action. Some boys have no interest whatever in sex. Others will show an intense curiosity spontaneously, a curiosity which perhaps may be explained as a larval precocity, dependent upon the minimum of sex hormone production by the gonads. Close observation of the correlation of somatic and psychic development in extreme examples of these children corroborates this view. Jonathan Hutchinson has described full-busted children of London already boasting of their affairs. Indeed, as education and environment affect the body (in so far as they influence it as a whole) by exciting or inhibiting the glands of internal secretion, sex-arousing stimuli from without must be considered to evoke their effects as stimulants of the latent puberty glands.

At puberty, when the sex glands bloom, and the complex of the sex instincts is activated, exhibitionism manifests itself in a host of guises and disguises. Femininity in a woman, the womanly woman, or the eternal feminine, may indeed be defined by the degree of somatic and psychic exhibitionism she presents. A woman who has a delicate skin, lovely complexion, well-formed breasts and menstruates freely will be found to have the typical feminine outlook on life, aspirations and reactions to stimuli, which, in spite of the protests of our feminists, do constitute the biologic feminine mind. Large, vascular, balanced ovaries are the well-springs of her life and personality. On the other hand, the woman who menstruates poorly or not at all is coarse-featured, flat-breasted, heavily built, angular in her outlines, will also be often aggressive, dominating, even enterprising and pioneering, in short, masculinoid. She is what she is because she possesses small, shrivelled, poorly functioning ovaries. Between these two types all sorts of transitions exist, according as the other endocrines participate in the constitutional make-up. But no better examples could be given, off-hand, of the determining stamp of the internal secretions upon mind, character and conduct.

INSTINCT AND BEHAVIOUR

The sex instinct, analyzed as an endocrine mechanism, provides the clue to the understanding of all instinct and behaviour. If the post-pituitary regulates the maternal instinct, then its correlates: sympathy, social impulses, and religious feeling, must be also influenced, and so is furnished another example of a chemical control of instinctive behaviour. McDougall, once of Oxford, now of Harvard, introduced into psychology the idea of the simple instinct as a unit of behaviour, regarding the most complex conduct as a compounding of instincts. The instinct itself he analyzed into three elements: a specific stimulus-sensation, an emotion following, all ending in a particular course of muscular reaction. Translated into endocrine terms, what happens may be pictured as a series of chemical events.

When the activity of a ductless gland rises above a certain minimum, its hormones in the blood sensitize, as a photographic plate is sensitized, a group of brain cells, to respond to a message from the outside world, with a definite line of conduct. There is a registration by the brain cells of the presence of the specific stimulus. Then there is communication by them with the endocrine organs. As a result, some of them are moved to further secretion, and others are paralyzed or weakened. In consequence of changes of concentration in the blood of the various internal secretions, tensions, movements and tumescences, as well as relaxations, inhibitions and detumescences, occur throughout the vegetative system—the blood vessels, the viscera, the nerves and the muscles. Each wires to the brain news of the change in it. In addition, the brain cells themselves are excited or depressed by the new hormones bathing them. In their final fusion, the commingling vegetative sensations constitute the emotion evolved in the functioning of the instinct.

To lower the new tensions throughout the vegetative system to the normal range, the instinctive action is carried out. This superficially is regarded as the essence of the instinct. As a matter of fact, it is only the endpoint of a process, the resultant of a drive to restore equilibrium within the organism. It may all happen in less time than it takes to tell about it.

The play of an instinct may therefore be analyzed into four processes. They succeed one another as sensation—endocrine stimulation—tension within the vegetative system—conduct to relieve tension. The dash is the symbol of a cause and effect relationship.

This equation for an instinct, based upon an analysis of the working of the sex instinct, is the model for the analysis of all instincts, and therefore of all the compounded instincts that all human behaviour may be resolved into. Conduct, that fascinator of the common gossip and the great novelist alike, normal and abnormal, social and asocial, in all their complexities, even unto the third and fourth generation, the Freudian complexes, is governed therefore by the same laws that determine the movements of the stars and the eruptions of volcanoes. The most interesting factor in the instinct equation is the endocrine, because that is the one that is most purely chemical.

ENDOCRINE CHARGING OF WISHES

It is the distinction of modern psychology that it has established the wish (craving, need, desire, libido) as the moving force in any psychic process. The position of the wish in psychology as the force within and behind the instinct may be compared to that of energy in physics, when it was elevated to a central position in the explanation of physical processes in the nineteenth century. The concept of the charged wish has illuminated all the hidden recesses and rendered audible all the subdued murmurings of the mind. The truly novel in the content of the idea is the recognition of the fact that the wish is charged. Now it could never be charged in a vacuum. That means that a wish could never be born in the brain alone. For the brain has no power to charge itself with energy—it can only store and transmit. If a wish is potential energy that must be transformed into kinetic, it must have a source. That source is the vegetative system. Without the vegetative system, the great complex of viscera in the abdomen and chest, blood and its vessels, endocrines, muscles and nerves, the brain would remain but an intricate cold storage plant of memories, associations of past experiences. It would need no change and initiate no effort. But when the wish enters upon the scene, it is as if a dead storage battery has been refreshed with new current. Enriched with billions of electrons there is a stir and a movement, dynamic mind. But the dynamo is the more ancient possession of the animal, the vegetative apparatus. In short, what must always be remembered is that a wish is never cerebral, but always sub-cerebral, visceral, in its origins.

The sub-cerebral makes the cerebral. Activities in the nervous system below the brain and especially the vegetative system, force upon it its function of the active verb. It has to be, to do, and to suffer, and then to manipulate the environment to satiate the insatiable viscera, insatiable because the local chemistry is continually raising the tension of one or the other of them. A physics of human behaviour becomes possible with the aid of these concepts of endocrine regulation of intravisceral pressure, and intervisceral equilibrium, an intramuscular pressure and an intermuscular equilibrium, with the brain as the shifting fulcrum of the system.

The sensation of hunger, as we have seen, serves as good an exemplar as any of this mechanism of the wish. Hunger is preceded and accompanied by contractions of the stomach of increasing intensity. Those contractions must be brought about by a substance acting upon the nerve endings in the wall of the stomach. As it closes down upon itself, waves pass up and down. With each wave, the pressure within it rises. The exact amount of the pressure may be accurately measured by means of a small balloon swallowed and then inflated. When the pressure rises above a certain figure, the sensation of hunger breaks into the consciousness of the individual. We infer that certain sensory impulses sent up to the brain attain a strength that finally forces itself into the conscious field of feeling. The sensation of hunger varies from individual to individual because of variation in the reaction throughout the vegetative system. Most often it is a sense of movement or even an itch in the upper abdomen. Let some cause produce a weakening or cessation of the movements of the stomach—as fear and anger—and the sensation of hunger disappears coincidently with the drop in the pressure within it. As the mathematicians would say, the wish is a function of the pressure, and so of the concentration of substance behind the pressure.

We have in hunger the wish reduced to the lowest terms, the most primitive form of it. Yet we may resolve all wishes, even the most idealistic, into the same terms. As the vegetative system becomes habituated by repeated experience to react in the same way to the same stimulus, permutations and combinations of wishes become possible until at length the inscrutable complexities of the behaviour of civilized man are evolved. We have to thank Von Bechterew, the greatest of Russian physiologists, for these fundamental principles, so important for the understanding of the control of human life and conduct.

The associated reflex, aboriginal ancestor of the involved train of associations that constitute the highest thought, conduct and character, is the unit of the system. Recall the classic example cited. If a piece of meat is shown to a dog, his mouth waters. If now you proceed to ring a bell before offering the meat, his mouth will water only when he sees or smells the meat. If, however, the ringing of the bell precedes the meat a sufficient number of reactions, a time comes when merely the sound of the bell will cause salivation, without the presence of the meat. So it is with the associated reactions of the internal secretions. A stimulus originally indifferent to the endocrines may, by association, the laws of which are many, come to act like a spark to the endocrine-instinct mechanism. Hence we can account for the subtle play of instinct throughout all thinking.

Even objects resembling the specific excitant of an instinct only remotely, or in some one quality, may start its mechanism and a host of associations bound up with it. Thus the maternal instinct may be excited by the sight of a baby. But because a baby is small and delicate, anything small and fine, a tiny book, a toy, a miniature, may arouse it. The object is then said to be appealing. The doctrine of association of instinctive and so of endocrine reactions enables us to understand the feeling—tone that at any moment pervades consciousness as well as its content.

Choices, the psychology of selection of food, color, friends, mates, amusements also become explicable rationally. For conflicts among the different components of the vegetative system are continuous and inevitable. If the pressure within a viscus has been heightened, and persists, that is, is not disturbed by some other associated factor or instinct, conduct results to lower the pressure to what it was before the instigator of the tension appeared. But if another instinct is sparked, or another associated factor comes into play, another focus of increased pressure within the vegetative system is created, with another stream of energy flowing to the brain and demanding an outlet. This clash of instincts, the struggle between different foci of the vegetative system competing for the possession of the brain, is a common everyday process in conduct. Which will win means which will will. And so we have an energetic basis for volition.

Which will win appears to depend primarily upon the kind of endocrines that predominate in the make-up of the individual, secondarily with his education. For it is the endocrines that are really in conflict when there is a struggle between two instincts. And if one endocrine system conquers, it must be either because it is inherently stronger, its secretion potential, that is, the amount of secretion it can put forth as a maximum, is greater (so explaining the term dominant)—or because a past experience has conditioned it to respond, although the opposing endocrine system does not. Fear and anger, respectively bound up with the activities of the adrenal medulla and cortex, we shall see, provide as good exemplars as any of this process.

The response of the ductless glands to situations varies with their congenital capacity, and acquired susceptibility. Capacity is a question of internal chemistry, modifiable by injury, disease, accident, shock, exhaustion. Susceptibility depends upon the play of the forces focusing upon them that may be summed up as associations. In the ability of one endocrine system to inhibit another we have the germ of the unconscious. Hence the modus operandi of the repressions and suppressions, compensations and dissociations, which may unite to integrate or refuse to integrate, and so disintegrate and deteriorate a personality.

As the personality develops, the vegetative system becomes susceptible to the manifold associates of family, school, church and society, art, science and religion, and last but not least sex. All the different nuances of personality are expressions of a particular relationship, transitory or permanent, between the endocrines and the viscera and muscles. Conversely, behaviour shows what a person actually is chemically; that is, what endocrine and vegetative factors predominate in his make-up.

FEAR, ANGER, AND COURAGE

Fear and anger are the oldest and so the most deep-rooted of the instincts. An ameba, contracting at the touch of some unpleasant object, feels fear in its most primitive form. And anger, the destructive passion, must have appeared early upon the scene of life. Certainly these two instincts were definitely developed and fixed in the cells before sex differentiation and the sex instincts were born at all. It is interesting to note this for our rabid Freudians.

Fear and anger involve the adrenal gland. How comes it that two states of mind so contrasted should involve the same area? The answer lies in the bipartite construction of the adrenal. All the evidence points to its medulla as the secretor of the substance which makes for the phenomena of fear, and to its cortex as dominant in the reactions of anger.

When adrenalin is injected under the skin in sufficient quantity, it will produce paleness, trembling, erection of the hair, twitching of the limbs, quick or gasping breathing, twitching of the lips—all the classic manifestations of fear. These are the immediate effects of fear because they are the immediate effects of excess adrenalin in the blood upon the vegetative viscera and the muscles. The perception by associative memory of these effects of adrenalin, the sensations arising from the organs affected, constitute the emotion of fear. Flight follows by muscle prepared for flight, for the disturbance of the inter-muscular equilibrium tenses the flexor muscles, the muscles of flight, and relaxes the extensor muscles, the muscles of attack.

If, it would seem, the cortex secretion now pours into the blood, enough to more than overcome the effects of the medulla secretion, the inter-muscular equilibrium is disturbed in the opposite direction, for fight rather than flight, and anger results. Or if the cortical secretion pours in an overwhelming amount of its secretion from the first into the blood there will be no fear, but anger immediately. Habitually charging and fearless animals like the bison, bull, tiger, or lion have a relatively larger cortex in their adrenals. Habitually fleeing and fearful animals, like the rabbit, have a small cortex and a wide medulla in their adrenals. The reinforcing action of the thyroid is important. The adrenal medulla reinforced by the thyroid makes for terror, the adrenal cortex reinforced by the thyroid makes for fury.

Some people are not easily frightened, others are more readily frightened, and still others are of an extremely fearful nature. It depends upon the proportion of adrenal cortex to medulla secretion in them. And their reaction to fear stimuli is a pretty good measure of the ratio. These formulations apply more particularly to fear in general and anger in general. But even in the least fearsome, i.e., an individual in whom cortex dominates medulla, there may be fear—complexes, dating back to events and times when medulla overtopped cortex, especially childhood. So in the coolest people, certain persons, objects, episodes, may send a wave along an old line of nerve cells and paths which lead to the adrenal medulla, and so flood him with fear, terror or even panic before his usual cortex response occurs. Impressions during the early years of childhood, probing of the unconscious by various methods, have been shown to be the most potent in this respect. Sometimes the episode goes further back than childhood, and one must assume an inherited conditioning of the vegetative and endocrine systems. An animal leaping upon an ancestor in a forest during the night might account for the panic fear some people experience when alone in the dark, that nothing of their childhood history may account for.

In women, the adrenal medulla naturally tends to overtop the cortex, because the latter makes for masculinity. Besides, the recurring cycle in the ovary, making the corpus luteum, evolves an additional stimulant to the medulla, through its irritating influence upon the thyroid. Then the influence of the post-pituitary is anti-adrenal cortex. So that, on the whole, a number of endocrines work to render woman naturally fearful, as we say.

Courage is so closely related to fear and anger that all are always associated in any discussion. Courage is commonly thought of as the emotion that is the opposite of fear. It would follow that courage meant simply inhibition of the adrenal medulla. As a matter of fact, the mechanism of courage is more complex. One must distinguish animal courage and deliberate courage. Animal courage is literally the courage of the beast. As noted, animals with the largest amounts of adrenal cortex are the pugnacious, aggressive, charging kings of the fields and forests. The emotion experienced by them is probably anger with a sort of blood-lust, and no consideration of the consequences. The object attacked acted like the red rag waved at a bull—it had stimulated a flow of the secretion of the adrenal cortex, and the instinct of anger became sparked, as it were, by the new condition of the blood. In courage, deliberate courage, there is more than instinct. There is an act of volition, a display of will. Admitting that without the adrenal cortex such courage would be impossible, the chief credit for courage must be ascribed to the ante-pituitary. It is the proper conjunction of its secretion and that of the adrenal cortex that makes for true courage. So it is we find that acts of courage have been recorded most often of individuals of the ante-pituitary type. Photographs are obtainable of thirty-four winners of the Congressional Medal of Honor for extraordinary bravery in the War with Germany. Of these twenty-three exhibited the somatic criteria or hormonic signs of the ante-pituitary type. A prerequisite for adequate ante-pituitary function is a normal secretion of the interstitial cells of the reproductive glands. Cowardice is said to be a feature of eunuchs.

THE PITUITARY AND INSTINCT

We have seen that, more than any other gland or tissue of the body, the post-pituitary governs the maternal-sexual instincts and their sublimations, the social and creative instincts. A great deal of evidence is in our possession concerning the disturbances of emotion accompanying disturbances of this gland, and controllable by its control. It might be said to energize deeply the tender emotions, and instead of saying soft-hearted we should say much-pituitarized. For all the basic sentiments (as opposed to the intellectualized self-protective sentimentalism), tender-heartedness, sympathy and suggestibility are interlocked with its functions. Its secretion must act upon the great basal ganglia, at the base of the brain, which contain the nerve cells and fibres that are the centers of emotional control and co-ordination.

The ante-pituitary has been depicted as the gland of intellectuality (to use that term for lack of better). By intellectuality we mean the capacity of the mind to control its environment by concepts and abstract ideas. The frontal lobes of the brain are the central offices for higher thought. Their cells are the most complex, have the most numerous branches and association fibres. They store the fruits of abstract thinking, mathematics, for example. The anterior pituitary is in the closest relation and contact with them. Its secretion is tonic to them. Now the instinct that is the forerunner of intellectuality is the instinct of curiosity, with its emotion of wonder, and its expression in the various constructive and acquisitive tendencies. Studies of intellectual men, and of those with a keen instinct of curiosity and a constructive-acquisitive trend prove them to be ante-pituitary dominant in their make-up. The administration of ante-pituitary extract to some defectives increases intellectual activity and self-control. The future of intelligence may expect a great deal from the newer chemistry of the secretions of the ante-pituitary.

Two most important instincts, therefore, which in the complexity of their sublimations have created most of the institutions of society, the maternal and the intellectual, are connected directly with a proper function of the pituitary endocrines. So it happens that disturbances of these instincts, reaching far into the normal and intellectual spheres of the mind, are definitely connected with disturbances of the pituitary. As we shall note in reviewing the essentials of the pituitary-centered or pituito-centric personality, the personality governed by the fluctuations of activity within the pituitary, people with injured, diseased or mechanically limited pituitaries (because of the smallness of the bony case enclosing them) exhibit defects and perversions of conduct and intelligence directly attributable to affections of the very instincts and functions the pituitary governs. Children with small, mechanically cramped pituitaries lie and steal, are bed-wetters, have poor control over themselves, and a low learning capacity.

THE THYROID AND INSTINCT

The chemical mechanism of the instincts described: sex libido, passion and jealousy in relation to the ovaries and testes, fear and anger in relation to the adrenals, sympathy and curiosity in relation to the pituitaries, suggests that a similar explanation will hold for the dynamics of the other instincts. In the closest relation to the thyroid appear the instincts first isolated, so to speak, by McDougall as the instincts of self-display and self-effacement, accompanied by emotions of pride and shame respectively. In certain states of excessive thyroid activity there is an extra stimulation of the instinctive display of the person which may go on to boasting, mania and exhibitionism. On the other hand, in states of thyroid insufficiency, depression is produced, which may go on to melancholia, a desire to be alone, to hide, to sit apart and even a tendency to accuse the self of various uncommitted crimes and sins. In the form of cyclic insanity known as the manic-depressive psychosis, mania alternates with depression, as if the personality were dominated wholly in turn by one or the other of these two instincts of the ego. There is a good deal of evidence that behind them is a corresponding fluctuation in the amount the thyroid secretes into the blood. Among the thyroid-centered attitudes toward the self gyrate more than in any other type. Egomania and megalomania occur most often in thyroid unstable individuals.

ENERGY AND SENSITIVITY

In his classic Inquiries into Human Faculty, Francis Galton laid down some fundamental considerations concerning energy and sensitivity as mental traits. Energy he defined as the capacity for labor, and declared it to be the measure of the fullness of life or vitality. Statistical study by him of men of genius and their ancestors showed them to be endowed with a large amount of energy. It has been said to be the absolute prerequisite of genius. Now if there is a single fact that has been well established by investigations of the internal secretions, it is that the energy quantum of an individual is a function of and determined by his thyroid. The more thyroid he has, the more energetic will he be—the less thyroid the less energetic, and the lazier. The thyroid-centered individual, of the excess thyroid type, actually burns up more food and produces more heat than the ordinary organism. He burns himself up faster in general.

When the thyroid sends more secretion into the blood, more thyroxin, it accelerates all the functions and activities of the organs. Tea and coffee produce loquacity because they stimulate the thyroid. People with thyroid dominant constitutions talk fluently, rapidly, and continuously. Their energy makes them doers, actors rather than spectators. They get up early in the morning, are on the go all day without surcease or fatigue, go to bed late, and often suffer from insomnia.

Thyroid deficients, however, are definitely the opposite. They are quite conscious of the limited reserve of energy at their command. Also that they need plenty of refreshing sleep. Early to bed and late to rise remains the leading maxim of health for them. In addition they find it necessary to sleep during the day. Forty winks or more in the afternoon makes a good deal of difference to them. Taciturn, inarticulate, lazy, slow, tired, are the adjectives applied to them by their friends as well as by their enemies. All because of an insufficient or inefficient supply of the thyroid's iodine to their cells. The mobility of energy in an organism is a measure of the amount of active iodine in it. The physiologic synonyms for "energetic and lazy" are "well-iodinized" and "poorly iodinized."

Sensitivity, the ability to discriminate between grades of sensation or acuteness of perception is another thyroid quality. Just as the thyroid plus is more energetic, so is he more sensitive. He feels things more, he feels pain more readily, because he arrives more quickly at the stage when the stimulus damages his nerve apparatus. The electric conductivity of his skin is greater, sometimes a hundred times greater, than the average. Conversely the thyroid deficient type has a low discriminative faculty. Galton has recorded that idiots hardly distinguish between heat and cold and that their sense of pain is so obtuse that some of the more idiotic seem hardly to know what it is. Cretins may moan but never shed tears.

Energy and sensitivity in an individual should direct attention to the thyroid element predominating in his composition. Lack of energy and insensitivity to the degree of thyroid insufficiency in their make-up.

MEMORY, JUDGMENT, AND POISE

In between sensitivity and energy, the sensation and the reaction, comes a passage of the stimulus through the gauntlet of the stored past experience of the individual known as memory. Many hypotheses have been advanced by philosophers, psychologists and physiologists to explain the phenomenona of memory. To conceive of memory materially at all one must admit some sort of memory trace as the basis for the persistence of memory. This memory deposit facilitates the occurrence of the chemical reaction constituting the memory along the same path the next time. Forgetting then consists in a disappearance of these memory traces or deposits. Forgetting is greatest in the first hour after remembering, more than half of the memory trace being lost in that time. Comparison of the curve of forgetting, and the curve of diffusion of a colloid like gelatine from its solution, into a surrounding medium, shows them to be exceedingly similar. Forgetting may be explained by some such loss of the memory trace or deposit into the blood continually flowing by it.

The internal secretions influence the amount and duration of the memory deposits. The thyroid appears to be essential to the laying down of the memory trace. Cretins have poor memories on the retention side and so cannot learn. The memory of thyroid insufficients is wretched. In the extreme grades, the memory for recent occurrences becomes completely lost. Iodine and thyroid increase the electric conductivity of the brain, so that the memory trace must be deposited more easily in those who have an excess of thyroid. Removal of the thyroid produces a degeneration of nerve cells and their processes, and associative memory becomes difficult or impossible because conduction from cell to cell is interfered with. If sufficient thyroid is fed in excess, brain conduction may be so facilitated that epilepsy may result upon slight irritation.

On the other hand, the pituitary seems to be related to preservation of the memory deposit. In conditions of disease of the pituitary, loss of memory for past experiences is more marked. As regards recent experiences, they are better held, although in a sort of subconscious manner, recoverable when the condition improves or is cured. But the greatest difference between the thyroid and pituitary effects upon memory exists as regards material: the thyroid memory applies particularly to perception and percepts, the pituitary to conception (reading, studying, thinking) and concepts.

Judgment is another mental process that often intervenes between sensation and the energy-reaction. It involves memory and association of experiences. Behind it is an attitude as much as there is in an emotion or the arousing of an instinct. Beliefs and reasonings are complex judgments. They form the units of the intellectual process.

There is an element of speed in judgment on reasoning as in perception and memory. And as in the latter, the thyroid determines the velocity. Quick thinking, as we call it, means good thyroid action, and slow thinking deficient thyroid action. The other element in judgment, accuracy, is influenced by the ante-pituitary. During adolescence there is physical growth which consumes most of the secretion of the ante-pituitary. After adolescence, after the early twenties, when physical growth has ceased, the ante-pituitary secretion sensitizes the cells of the brain to mental growth. The reaction potential of the ante-pituitary, that is its inherent, latent ability to supply a maximum of its endocrine for the nerve cells of the frontal lobes, is the best-known chemical determinant of intellectual genius. It makes for the greatest co-ordination of experience, knowledge, information, tastes and problems into one harmonious whole. And curiously, not only does it cause a fusion of intellectual material: it creates a desire for and a love of such material.

We should expect to find extraordinarily well-developed ante-pituitary action among eminent philosophers and men of science, and we do. Adequate action of it is present throughout the range of normals who evidence sufficiently ripened judgment as they progress through life. The ability to profit by experience, and to make more and more accurate judgments as one grows older implies at least a maximum efficiency of it. This maturation is not at all universal. Even after middle age, after forty and fifty years of reasoning, some individuals retain the juvenile mind of their youth. Like the Bourbons, they have learned nothing and forgotten nothing. Their ante-pituitary insufficiency often coupled with a post-pituitary excess, and other instabilities and disequilibriums in the endocrine system, render them immature morons, compared with what might be expected of them for their years. They are the people who are old enough to know better. For the same reasons, inhibition and emotional control are poor in them.

Besides the ante-pituitary, in the evolution of judgment, and the judgment faculty, due stress must be laid upon the influence of the internal secretion of the testes or ovaries, the product of the interstitial cells. Although the probability is that the effects are indirect, through a stimulation of the ante-pituitary, the fact remains that, in a child, memory may be marvelous and judgment poor (such memory is possibly purely thyroid in its determination). With the advent of the gonads upon the scene, judgments become the centre of the play's plot undoubtedly. The intelligence of eunuchs and eunuchoids is in general low. The skull and brain of castrates, animal and human, is smaller than the average. Gall, the physiologist who popularized ideas concerning the meaning of the protuberances and depressions of the head in relation to faculty and character, early in the nineteenth century, was the first to prove this. Among historic castrates, eunuchs, not a single example of great intellect, of the creative type, is known. On the contrary, the native gifts of the mind were destroyed. Thus Abelard, who was punished with castration by his uncle for his love affair with HelÖise, never composed a verse of poetry thereafter.

IMAGINATION AS AN ENDOCRINE GIFT

That brings us to the consideration of imagination as influenced by the endocrines. The physical conditions of exercise of the imaginative faculty have not been sufficiently investigated. Alcohol has long been known to act as an evocant of strange images. The hallucinations of delirium tremens are the results obtained in extreme intoxication. A strangely imaged flow of consciousness, the imaginative state, may also be evoked by morphine and cannabis indica. There is no doubt that the brain cells may be made to combine in the fresh, novel, and unfamiliar associations that are recognized as unreal.

Francis Galton, pioneer student of the conditionings of human faculty, left an interesting study of the visualising capacity, so far as it could be attacked by the statistical method. Two of his conclusions are worth repeating for our purposes. One is that the power to imagine is poor in philosophers and men of science. The other that it is higher in the female sex than in the male. We have seen that the philosophic, scientific, intellectual mind, the capacity to abstract, and think in terms of abstractions, is definitely dependent upon proper secretion by the ante-pituitary. In woman, the post-pituitary is generally predominant over the ante-pituitary. Though we are in need of a series of studies of the endocrine traits and composition of men endowed with high imaginative qualities, and so are at a loss, we have indications of an endocrine control of the state of consciousness we speak of as the imaginative.

Most of the evidence accumulated in the examination and treatment of morbid conditions characterized by a restless, incoordinate activity of the brain cells points to excess of the post-pituitary secretion as the cause, or as one of the most important causes. The thyroid and the adrenal medulla also exert their influence. But the strongest appears to be the post-pituitary. Phobias, fears which obsess the mind, anxiety neuroses, suspicions, hallucinations, delusions, nervousness, all expressions of what we may sum up technically as the imaginative state of mind, occur and occur frequently, associated with other symptoms of posterior pituitary overactivity. Persons in whose make-up it rules are more liable to imagine disturbances of their mentality, or exhibit a well-developed imaginative streak. Normal states of overactivity of the post-pituitary such as occur in some women during the menstrual period and pregnancy, and in some men as part of the endocrine cycle of their everyday lives, are accompanied by increase in the susceptibility and vigor of the imagination. Whether the feeding of excess post-pituitary would lead to a stimulation of the tendency or ability to imagine is still to be decided. But it is known that quieting the post-pituitary by various means will cause a depression of the faculty, and eliminate its pathologic manifestations.

Psychologists distinguish between the constructive imagination that expresses itself in an ordered activity and the unbalanced fancies of the fearful neurotic for example. The post-pituitary confers the lability of the underlying state of brain in all of these imaginative tincturings of consciousness. The constructive imagination, one of the few truly precious gifts of a personality, is probably the expression of a certain balanced activity of the ante-pituitary and the post-pituitary.

MOODS AND THE ORGANIC OUTLOOK

The lability the post-pituitary confers upon the combinations of perceptions and conceptions, grouped as the imagined, extends to the ruling mood that may be spoken of as the organic outlook. Post-pituitary in excess, without compensation or balancing by one or some of the other endocrines, is associated with an instability of mood and the organic outlook. Concomitant is a defective self-control. Typically, one sees the effects in the mental abnormalities of women during the premenstrual period. A number of them have their pituitary balance upset then, with an overtopping of the ante-pituitary by the post-pituitary. Irritability, a sub-hysteria, or an actual hysteria may emerge in the usually most placid characters. A quiet wife and mother may go for her husband, curse and mortify him, even strike and beat him. She may slap her children at that time and no other. It is well known that most of their crimes are committed by women during the menstrual period. So are the suicides. Deterioration of mentality and character so often observed during the menopause, with its apathies or excitements, melancholia or mania, the fits of weeping or gaiety, the loss of grip upon reality, the complete change in mood and temperament that reflect the transformation of the organic outlook, demonstrate clearly the overwhelming influence of the endocrines upon the attitudes of the self toward the self.

It is possible to speak of thyroid moods, adrenal moods, ante-pituitary or post-pituitary moods, gonadal moods. Each of these is the echo in the mind of cells stimulated or depressed, by concentration or dilution in the blood of particular internal secretions. Restlessness and excitement can be produced experimentally by feeding thyroid. Vague anxiety, depressive fancies and fears, imaginative overactivity can be removed by inhibiting the post-pituitary. Hypersecretion of the ovary will cause a sexual susceptibility and a mood of genital obsession, capable of the most remarkable sublimations and perversions.