Chapter 5 HOW THE GLANDS INFLUENCE THE NORMAL BODY

The origin of the remarkable differences between individuals that distinguish species, varieties and families, has long been one of the chief puzzles of biology. It may indeed be called the leading puzzle, which led Darwin on to the collection of the data that culminated in the "Origin of Species." The why of the Unique is the fundamental problem of those who would understand life.

An explanation is an attempt at a consistent and persistent, sometimes an obstinate clarity of mind. A vast number of observations gathered by laboratory experimentalists as well as by those naturalists of the abnormal, physicians in active practice, prove that the construction of the individual both during development before maturity, and maintenance during maturity, his constitution, in short, is directed by the endocrine glands. It is possible now to present an explanation of the individuality of the individual.

To assert that variation is responsible for the individual, that it is the mechanism which isolates him as a being like none other of his fellows, not even his parents, brothers, and sisters, is merely to beg the question. What is variation? The internal secretion theory of the process offers, for the first time, an explanation that is coherent and comprehensive, based upon concrete and detailed observations. It provides an adequate interpretation of the numberless hereditary gradations and transitions, blendings and mixtures. It suggests a control of heredity in the future.

THE PURE TYPES

In the pure types, only one gland, either by being present in great excess above the average, or by being pretty well below the average, comes to exercise the dominating influence upon the traits of the organism. As the strongest link in the chain, or as the weakest, it rules. The others must accommodate themselves to it. Among them as commanders of growth, development and normal function, it holds the balance of power. In every emergency it stands out by its strength or by its weakness. It thus creates its own type of man or woman, with attributes and characteristics peculiar to itself. These pure types, as we have seen, are mainly the thyroid, the pituitary, and the adrenal-centered.

Each with the signs peculiar to it can be identified among the faces that pass one in the street. And they differ so markedly among themselves that they provide a new and accurate means of classifying varieties among the races of the species: man. The thyroid type differs as much from the adrenal type as does a greyhound from a bull-dog. The greyhound has a certain size, form, character and capacity. The bull-dog has similar qualities which are yet quite different. Each is built for a particular career. Among human beings, the pure thyroid type is easily distinguished from the pure adrenal type, and both of these from the pure pituitary type. Each is stamped with a significant figure, height, skin, hair, temperament, ambition, social reactions and predisposition to certain diseases.

THE MIXED TYPES

Among the mixed types, the lines of distinction are less clear, and so they are more difficult to classify. The mixed types may be said to be hyphenated. In them, two or even three of the internal secretory glands conflict for predominance. The combined action makes for a resultant modification in the primary glandular markings and effects. A hyphenated classification thus becomes inevitable. Especially is this so if the two glands are mutually antagonistic and inhibitory. A compromise effect is then necessitated. Or an individual may be dominated by one gland at one period of his life and by another at a later period. One of the glands, the thyroid, for example, will show, by the traces it has left upon the earliest developing features, that it was in control at the very earliest dates of his history, while other signs will disclose the more recent influence of the adrenal or of the pituitary. The combination becomes classifiable as the thyroid-pituitary type, or as the thyroid-adrenal type.

That the external features as well as the chronic diseases of human beings are controlled by some common factor has long been suspected. Inquiries into morbid phenomena with a hereditary trend yielded information that has paved the way for the internal secretion theory. It has long been known that certain diseases effect only certain individuals of a definite constitution. Apoplexy, diabetes, arteriosclerosis, Bright's disease, are met with almost exclusively in what the older clinicians talked about as the apopleptic type. On the other hand, they said, anemias, tuberculosis, hemophilias, scrofulas occurred more among the lymphatic type. But they had no idea whatever of the true functional basis of the two different types. The truth as we of today view it is that these two types represent different textures of human beings, fabricated of different internal secretions. They are really two different breeds of the species Homo Sapiens. The materials being different, the color and feel of them is different, and the resistance to wear and tear is different.

ENDOCRINE ANALYSIS

The modes of classification glimpsed at are certainly exceedingly broad and sweeping. It is well enough to establish types and classes. But beneath them are sheltered the infinite possibilities of permutations and combinations, which explain the countless variety and complexity of form and function. Every individual born among the vertebrates, for example, must have a certain definite amount and percentage of pituitary gland, anterior and posterior, pineal, thyroid, parathyroid, thymus, adrenal, pancreas, interstitial and so on. Now if, to state it in terms of percentages, for the sake of argument, the pituitary is 25, the pineal 10, the thyroid 36, the parathyroids 15, the thymus 29, the adrenals 60, the pancreas 49, the interstitials 72 (the gland when acting maximally to be graded as 100), we see at once how different such an individual must be from one who has, say, pituitary 84, pineal 39, thyroid 26, parathyroid 42, adrenals 96, pancreas 22 and interstitials 89. One obtains at once from the contrasts of such figures some idea of the possibilities. As each point plus or minus must count to produce some difference in the individual, the results are manifest. Varying within the numerical limits imposed by genus, species, variety and family (which limits are probably responsible for the persistence of the particular genus, species, variety, or family) the individual becomes an individual because of the relative values of the percentages in his blood and tissues of these different internal secretions. We thus begin to gain an insight into the patterns according to which men, women and animals are woven.

We are, as yet, far from an exact endocrine analysis of the individual. But we know that the endocrines rule over growth and nutrition, a vast dominion which incorporates every organ and every tissue. By enhancing or retarding the nutritional changes, the growth of the organ or tissue is favored or restricted. The size and shape of an individual, as a whole, as well as of the specialized cell masses composing him, as hands and feet, the nose and ears, and so on, are therefore controlled by them. Whether an organism is to be tall or short, lean or corpulent, graceful or awkward, is decided by their interactions. These, like human covenants, vary with the different reactions of the parties to the contract. And so a great deal depends upon whether they work harmoniously or discordantly, and upon which does the most work and which the least.

Undersecretion and Oversecretion

It is when a gland, either in the course of development, or because of the influence of starvation, shock, injury, poisoning or infection, begins to undersecrete or oversecrete that its effects upon growth and nutrition become grossly manifest. A veritable transfiguration of the individual may occur, the black magic of which may perplex him for a lifetime. A man, made eunuchoid by an accident or by mumps, will observe in himself astonishing changes in his constitutional make-up, mentality and sexuality. He would be more astounded to learn that beneath the appearances, the changes, so alarming him, there are profound alterations in the rate at which he is taking in oxygen, burning up sugar, accumulating carbon dioxide and excreting waste byproducts through the kidneys, which are responsible for them.

The differences between the normal and abnormal are only a matter of degree. And so, to be sure, are differences between types. But it is hard to realize that the striking distinctions between the thyroid type and the pituitary, comparable, as said, to the differences between a greyhound and a bull-dog, are dependent solely upon quantitative variations in the general and local speeds of metabolism, among the cells.

DIVISION OF LABOR

Besides the antagonisms and co-operations between them, there are certain lines along which the glands, in their effects, specialize. The thyroid, for instance, is concerned specially with the regulation of the shape, form and finish of an organ. The pituitary shines at the periods of developmental crises, determining them and modifying them. It exerts the greatest influence upon the time of eruption of the teeth, both the temporary and the permanent, the onset of puberty, the recurrence of menstruation in women, and the time of occurrence of labor. The interstitial glands distribute the basis of the powers and limitations of masculinity and femininity. Abnormalities of these glands also affect the individual all along the line, in all of his aspects. So affected he may apparently change into a wholly different being. He may change in size, in the shape of his head, feet and hands, as well as in his habits, aptitudes and dispositions. So he may find it necessary to purchase an entirely different size of hat, more commodious clothes, and newly fitting gloves and shoes. At the same time, his family, relatives and friends, discover that the erstwhile generous, frank, neat and punctual and liked, has become stingy and suspicious and slovenly and hated. And all because a gland has begun to undersecrete or to oversecrete. The transformation will be slight or marked, depending entirely upon the extent of impairment, positive or negative, of the gland involved.

But it is not only in the shaping of the normal individual's architecture that the internal secretions dominate. Over that subtle something known in all languages as vitality, expressive of the intensity of feeling, thought and reactions in cells, they rule supreme. Gay vivacity and grim determination, the temperament of a Louis XIV, and the soul of a Cromwell, are the crystallizations of these chemical substances acting upon the brain.

INTERNAL SECRETION VARIETIES

There is no better way of illustrating the influence of the internal secretions upon the normal than the analysis of the variation of traits with variations in glandular predominances. The general build of an individual, his skeletal type, the proportion between the size of his arms and that of his legs, as well as that between his trunk and his lower extremities, whether he is to be tall, lanky and loutish, or short, squat and dumpy, are to be considered. Different facial types are the expressions of underlying endocrine differences. The head and skull offer a number of clues to the controlling secretions in the blood and tissues. Whether the forehead is to be broad or narrow, the distance between the eyes, the character of the eyebrows, the shape and size and appearance of the eyes themselves, the mould of the nose and jaws and the peculiarities of the teeth, are all so determined. The skin, in its color, texture, the quantity and distribution of its fatty and other constituents, eruptions and weather reactions, is influenced. Also the mucous membranes, the color and lustre and structure of the hair, as well as its general distribution and development, are hieroglyphics of the endocrine processes below the surface. Whether the muscles are massive or sparse, atrophied or hypertrophied, soft or hard, easily fatigable or not, bespeak conditions in the glandular chain. In short, we must regard the individual as an immensely complicated pattern of designs traced by the hormones as the primary etchers of his development. Though it must be admitted that the number of unknown and unsolved relations in the pattern are still enormously great, enough has been established to make possible a rough working analysis of the particular, unique organism placed before us for examination as Mr. Smith, Mrs. Jones, or Miss Smith-Jones.

WHAT IS THE NORMAL?

Anthropologists, from the beginning of anthropology, have battled in vain for a satisfactory inclusive definition, or, at least, description of the normal. With the introduction of the biometric method, the goal at last appeared within sight. A cocked hat curve expressing the distribution and range of the normal looks formidable. The attainable turned out a mirage, for the curves constructable by the measurement of traits of a population only proved the truth of the old axiom that all transitions and variations between extremes exist. The Problem of the Normal seemed more elusive than ever. And the best that could be done for the elucidation of its mystery, was to apply and observe the law of averages.

From the endocrine standpoint, the reason for this becomes clear. The biometric method concerned itself with externals, with, as it were, symptoms. Since these external signs are but manifestations of the inner chemical reactions, of which the internal secretions are the determining reagents, or factors, with permutations and combinations possible in all directions, the diversity and variability of each individual and his traits stands explained and understandable. The normal, as the perfect or nearly perfect balance of forces in the organism, at any given moment, emerges as a more definite and real concept than that which would abstract it from a curve of variations. Moreover, since the directive forces within the organism are pre-eminently the internal secretions, the normal becomes definable as their harmonious balancing or equilibrium, a state which tends not to undo (as the abnormal does) but to prolong itself.

The potential combinations and compensations, antagonisms and counteractions, attainable within the endocrine glands as an interlocking directorate, point the cause for the elusive quality of the normal. Tall men and short men, blonde women and dumpy women, lanky hatchet-faced people, stout moon-faced people, Falstaff and Queen Elizabeth, George Washington and Abraham Lincoln, Disraeli and Walt Whitman, Caesar and Alexander, as well as Mr. Smith and Miss Jones come within the range of the normal. There are all kinds and conditions and sorts of men and women, and all kinds and sorts and conditions of the normal, because an incalculable number of harmonious relations and interactions between the endocrines are possible, and do actually occur. The standard of the normal must obviously not be a single standard, but a series of standards, depending upon which glands predominate, and how the others adapt themselves to its predominance. Adrenal-centered types, thyroid-centered types, pituitary-centered types, thymus-centered types, as well as hyphenated compounds of these, such as the pituitary-adrenal types, exist as normals. They can be conceived of as normal types because they exist as normal types.

THE SKELETAL TYPES

Now men, for as long as we have any knowledge of their thoughts and classifications and attitudes, have been accustomed to first think of one another, to classify and size one another as tall or short, slender or broad, thin or corpulent. The biological necessity, indeed, instinct of the one animal to relate the other animal to aggressive or harmless agencies in his surroundings, accounts for this. Relatively, of course, for all these modes of description imply offensive or defensive possibilities of the stimulus for the recorder in relation to himself. The interest in stature is fundamental, and has persisted in the most civilized, nations. The relationship of height and weight, as well as of length and breadth, to other physical traits, have formed the subject of scientific study. There is, for instance, the classification of Bean, who divided mankind generally into two types, those of a medium size, stocky long legs and arms, large hands and feet, short trunk, and face large in comparison to the head (the meso-onto-morphs) and those who were either tall and slender, or small and delicate, with the smaller face, eyes close together, long, high, narrow nose, and trunk longer as compared with the extremities (the hyper-onto-morphs). Bean showed, too, that the hypers (to use a short word to contrast with the mesos) were present to the extent of almost a hundred per cent in a series of tuberculosis, and about ninety per cent in a series of central nervous system disease. All of which is exceedingly interesting and suggestive, but throws no light upon the underlying mechanisms of statures.

STATURE AND GROWTH

Stature is essentially determined by the growth of the long bones. They are the pace-makers, and the muscles and soft tissues follow the pace they set. Now the primary determinant, catalyst or sensitizer of the growth of the long bones is the anterior pituitary. All statures should therefore be first scrutinized from the point of view of the pituitary. Individuals over six feet tall or under five feet five inches should be looked upon as having a pituitary trend. This pituitary trend may be primary, due to its own undergrowth or overgrowth, or it may be due to lack of inhibition from the sex glands such as occurs in eunuchs and eunuchoids, or excessive or premature inhibition from them as happens in certain salacious dwarfs.

The long bones grow at a point of junction between the bone proper and an overlying layer of gristle or cartilage, known as the zone of ossification. It is upon this zone of ossification that the various growth influences appear to focus and concentrate their efforts, among them the internal secretions. After growth has been finished, that is, after adolescence, these zones of ossification close, so that growth is no longer possible unless they become reactivated. Upon the zone of ossification must act the pituitary, and indirectly the thyroid, the interstitial cells, the thymus and the adrenals. Individuals oversized or undersized either belong to the pituitary type, or if hyphenated, have the pituitary as one of the dominants in their composition. The necessities of child-bearing determine a greater angle between trunk and lower extremities in the female. Underactivity of the pituitary, for instance, will prevent the development of the normal angle. The ratio in length of the upper limbs to the lower is a fairly constant relationship for each sex normally Deviations occur with a break somewhere in the chain of cooperation of the internal secretions controlling the growth of bone.

HANDS, FINGERS AND TOES

The size and shape and general configuration of the hands, fingers and toes are details that tell an endocrine tale. Students of hands naturally have grouped them as the long slender and the short, broad, the bony and the well-filled out, the tapering fingers and the stumpy. The character of a hand is determined anatomically by the length and breadth of the bones, the amount and distribution of fat, and the thickness and elasticity of the skin. Over these, the essential control lies in the pituitary and the thyroid. So we find that pituitary types have, when there is oversecretion, large bony, gross hands, spade-shaped, or when there is undersecretion, hands that are plump, with peculiarly tapering fleshy fingers. The hyperthyroid has long slender fingers, the subthyroid pudgy, coarse, ugly foreshortened hands, often cold, and bluish.

FACIAL TYPES

An artist will see in a face the past history of generations, a narrative of the adventures of the blood, a record of tears and smiles, wrinkles and dimples, the victories and defeats of buried drudgery and romance. These signatures which the Faculty of Life have scribbled or engraved over it as upon a diploma, bespeak for him spiritual moments. To the student of the internal secretions the lines, expressions, attitudes are important for they tell of the state of tensions and strains in the vegetative apparatus with which they are inseparably connected. It is when one comes to the consideration of the face as a complex of brows, eyes, nose, lips and jaws that he becomes most interested. For in the modeling and tone of every one of the features each of the endocrine glands has something to say. In consequence there has been described the hyperpituitary face, and the hyperthyroid face, the subthyroid face and the subpituitary face, the adrenal face, the eunuchoid face and the ovarian face and also the thymic.

To bring to mind an immediate complete image of the hyperthyroid face, one should think of Shelley. The oval shape of it, with the delicate modeling of all the features, the wide, high brow, the large, vivacious, prominent eyes with the glint of a divine fire in them and the sensitive lips all belong to the classical picture. Generally flushed over the cheek-bones, there is undoubtedly a certain effeminate effect associated with it. At least, it is the least animal and brutish of the faces of man.

On the other hand, the subthyroid face is that of the cretin and cretinoid idiot, in a mild degree. So characteristic that we recognize the portrait in the descriptions of Pliny in early Roman tunes and of Marco Polo in his Asiatic travels. Coarseness, dullness, pudginess are its keynotes. Irregular features, tendency to wide separation of the eyes and pug nose, sallow, puffy complexion, waxy thickened nose and eyelids, deep-set, listless, lacklustre eyebrows, and thick prominent lips comprise the catalogue of the physiognomy. On the whole, the sort of face one passes in the street as stupid and common. But there are a number of fascinating and marvelous varieties of the stupid and common.

The adrenal face is most often dark or freckled. It tends to be irregularly broadish. It is hairy, one is struck forcibly. There is a low hair line, which makes the brow appear rather low, and there is a good deal of hair over the cheek bones. The adrenal type is round headed.

The face of the hyperpituitary is striking and pretty sharply defined. It is long and narrow, with a tendency to prominence of the bony parts. Square, protruding jaw, high, thin, straight nose, emphasized eyebrows, and marked cheek-bones, comprise the leading points in its composition. On the other hand, the subpituitary is more rounded and trends toward the full moon effect, the chin recedes, the cheek-bones are buried under fat, the nose spreads more and is flatter. In its general expression, there is a complacence and tranquillity which is often mistaken for sleepiness, and often actually is dullness.

The eunuchoid face is usually fat with puffy eyelids. The skin is smooth and cool, marble-like often, poor in pigment and color. Sometimes it is sallow, wrinkled and senile in a man in his early twenties. At others, it is distinctly feminine in its hairlessness, and the delicate texture of the skin, as well as in the clean-cut patterning of the features. Every gradient between premature senility and sex inversion is encountered.

The thymic face frequently stamps its possessor at sight. Its owner has a smooth, soft skin, with little or no hair, and a dead white or "peaches-and-cream" complexion. One wonders, when unacquainted with the type, who the man's barber is, or where he learned to shave himself so well. It may be curiously velvety to the touch and swept by a faint sheen. Among children occur the most exquisite samples of the kind designated as the angelic child. The face is finely moulded and beautifully proportioned, features artistically chiselled, eyes blue or brown with long lashes, cheeks transparent with rapid, fleeting variations in coloring, thin lips, and oval chin. In the adult, the chin is receding, and the mouth seems underdeveloped in one variety.

THE TEETH

As closely connected with the internal secretions as are the bones of the face and the skull are the teeth. Tooth formation is essentially a modified bone formation. And as the bones of the face are influenced, so are the teeth influenced. But as each tooth is a miniature organ, inspectable by the eye as a unit, the action of the ductless glands is more obviously reflected for the observer to read. By their teeth shall ye know them. Upon the whole history of the evolution of each tooth, in the growth of the dental follicle and its walls, the fruition of the dentinal germ, the making of the enamel organ, the dental pulp, the cementum and the peridental membrane, the endocrines leave their mark.

There are certain general statements about the teeth and the internal secretions that can be made. The teeth of the thyroid types are pearly, glistening, small and regular; in other words, the teeth to which poets have devoted sonnets. The pituitary types have teeth that are large and square and irregular, with prominence of the middle incisors, and a marked separation or crowding of them. The interstitial types have small irregular upper teeth, with turned, stumpy or missing lateral incisors. The thymus types have youthful, milky white teeth that are thin and translucent, and scalloped or crescentic at the grinding edge. The teeth of the adrenal type are all well-developed, tend to have a yellowish color, with a reddish tinge to the grinding surfaces.

The degree and regularity of development of the middle upper cutting, biting teeth, as distinguished from the grinding molars, the middle and lateral incisors, and the canines offer further guides to the endocrine constitution analysis. The size of the central incisors seems to be directly proportional to the degree of pituitary predominance. On the other hand, the size and regularity of the lateral incisors seem proportional to the influence of the interstitial cells. When these are inferior in the make-up of an individual, the lateral incisors are nearly always distorted. The size of the canines appears to be a measure of adrenal activity. Long sharply pointed canines mean well-functioning adrenal gland equipment to start in with, inherited from a bellicose progenitor.

No individual peculiarities of the teeth are accidental. Just as the absence of hair on the face in a man or a moustache effect in a woman stand for some definite stress or strain in the mechanics of interaction of the internal secretions, so likewise do variations in dentition, as to the time of eruption of the teeth, their position and quality, and their resistance to decay.

Proper balance between the thymus and pituitary will permit the eruption of the teeth within the normal time limits, both the milk teeth and the permanent teeth. When there is equilibrium between the pituitary and the gonads, the teeth will be regular in shape and position. Carious teeth, in children and adults, sometimes indicate endocrine imbalance. Thyroid and adrenal balance determines the resistance to decay of the molars. Early decay of the molars in children is significant of insufficiency of the thyroid. When the first permanent molar, which should appear in the upper arch in its usual position between the sixth or eighth years, does not, there has been a prenatal disturbance of the pituitary, according to Chayes and others. Rapid decay of the teeth in childhood should always call attention to the parathyroids.

In pregnancy, the teeth suffer particularly because of disturbances of the endocrines. The saying, "A tooth for every child," is said to have its equivalent in every language. The bicuspids and second permanent molars erupt around puberty, when profound readjustments are going on among the glands of internal secretion. They consequently suffer with their abnormalities or divergences from type. The teeth thus furnish a good deal of information concerning the distribution of the balance of power among the hormones.

THE SKIN

The skin is influenced in its color, moisture, hairiness, texture, fat content and disease vulnerability by the endocrines. The question of color is very interesting, for it is probably the expression of the blending action of the different internal secretions. Davenport, the American student of heredity and eugenics, has shown that neither white nor black skins are either perfectly white or perfectly black, but are mixtures in various proportions of black, yellow, red and white. The exact percentages of the pigments in each particular skin, can be determined by means of a rotating disc. Thus a white person's skin may have the following composition:

Black 8% Red 50%

Yellow 9% White 33%

The composition of the skin of a very black negro may be:

Black 68% Red 26%

Yellow 2% White 7%

Now the fact that in Addison's disease in which the adrenals are destroyed there occurs a coincident increase in the black in the skin, and other evidence pointing to adrenal implication in dark complexioned white people, as well as in those possessing pigmented spots, seems to indicate the adrenals as controllers of the black and white factors. Davenport has concluded that there are two double factors for black pigmentation in the full-blooded negro which are separately inheritable. The determinants of the red and yellow have still to be worked out.

The moistness of the skin, as perspiration, depends upon the number and activity of the sweat glands. It varies with the water content of the body, the state of the vegetative nervous system, and the body temperature. Thus the skin of the hyperthyroid and the subadrenal is soft and moist, because of their antagonistic effects upon the sympathetic system. The subthyroid and the hyperadrenal have dry and harsh skins for the same reason, if no other glands intervene. However, in both of the latter, if there is a persistent thymus, the skin will retain the bland quality of adolescence.

There is a curious variation among the different internal secretion types in the reaction of the skin to stroking. When the skin, especially the skin over the shoulders, the breasts and the abdomen, is stroked with some blunt object, the blood vessels react either by a greater filling up or emptying of themselves. The latter occurs most regularly in the subadrenal types, the former in the hyperthyroid. Both forms of reaction run parallel to the different check or drive effects of the vegetative apparatus. With too much drive, that is, too much thyroid, there is the flushing reaction; with too little check, that is, with too little adrenal, there is the whitening. These differences probably explain the emotional reactions of the face. In anger, for example, some people become a dead white, others a fiery red. Whether one will do one or the other may depend upon the relative predominance of the thyroid or of adrenal in the individual.

In the distribution of fat beneath and throughout the skin all of the endocrine glands appear to have a voice. The typically hyperthyroid and hyperpituitary individuals tend to be thin, as well also as those who have well-functioning or excessively functional interstitial cells. In all of these the administration of the respective internal secretions increases the burning up of material in the body, and all of them have a higher rate of tissue combustion than their confreres, with a subthyroid or subpituitary keynote in their cell chemistry, or with insufficient interstitial cell action. Generally the latter have a very dry skin, the former a moist skin. With delayed involution of the pineal, obesity results.

The elasticity of the skin is another quality that varies with the concentration in the blood of the internal secretions. Elasticity of the skin, its recoil upon being stretched like a rubber band, may be taken as a measure of the activity of all the endocrine glands. For, as can be noticed especially upon the back of the hand, the older a man grows, the less elastic becomes the skin. In older people, raising the skin upon the back of the hand will cause it to stand up as a ridge for a few seconds and then slowly to return to the level of the surrounding skin. Whereas in a youthful person it will quickly snap back into place. This quality of elasticity of the skin is due to the presence in it of the so-called yellow elastic fibres, cell products, with a resilience greater than anything devised by man. The preservation of the resilience is a function of the internal secretions. Thus, after loss of the thyroid, the ridging effect characteristic of senility can be produced in one young as measured by his years. It has been said that a man is as old as his arteries, and also that as he is as old as his skin. It might better be said that he is as old as his elastic tissue, young when he is rich in it, old when poor and losing it. And as elastic tissue and internal secretions stand in the relation of created and creators, or at least preserved and preservers, a man may be said to be as old, that is as young, fresh and active as his ductless glands.

THE HAIR

There is no characteristic of the human body, except perhaps the teeth, more influenced in its quality, texture, amount and distribution than the hair. And again, each of the glands of internal secretion plays a part, but most importantly the thyroid, the suprarenal cortex and the interstitial sex glands. All contribute their specific effect, and the blend, the sum of the additions and subtractions constituting their influences, appears as a specific trait of the individual, a trait so significant as to be used by the professionals absorbed in the study of man, the anthropologists, as a criterion of racial classifications.

Some acquaintance with the history of the normal growth of hair is necessary to its understanding. There develops during the life of the fetus within the womb a curious sort of wooly hair everywhere over the entire body (excepting the palms and soles which remain hairless throughout life), remarkably soft and fluttery-the lanugo. At about the eighth month of intra-uterine existence, a good deal of this lanugo is lost, to be replaced on the head and eyebrows by a crop of thick, coarse, pigmented real hair. So it happens that at birth the infant's hair is a queerly irregular growth, a mixture of what is left of the general lanugo development, and the localized patches of the more human hair. Until puberty this children's hair remains the same, although at times, particularly after dentition, and after infectious diseases which undoubtedly alter the relations of the internal secretions, changes of color and texture occur. Then, with sexual ripening, there appear in males the so-called terminal hairs, over the cheeks and lips and chin, and, in both sexes, in the folds under the shoulders and over the lower abdomen, the hair which might be distinguished as the sex hair in contradistinction to the juvenile hair of the head, the extremities and the back.

Now the smoothness of the face in children is connected with the activity of the thymus and pineal glands. Among individuals in whom the juvenile thymus persists after puberty, no growth of hair occurs on the face, and in precocious involution or destruction of the pineal, hair appears on the face and in other terminal regions in children of six or less, a symptom classical in the child who suffered from a tumor of the pineal, and discussed immortality with his physicians. It is probable that these thymus and pineal effects are indirect through their action upon the sex glands. For in the types with persistent juvenile thymus there occurs a maldevelopment of the sex glands, while in those with early pineal recession the sex glands bloom simultanously with the appearance of adolescent hair and mental traits. The hastening of sexual hair by tumors of the adrenal gland may also be put down to a release from restraint of the interstitial sex cells.

There are certain spheres in the hair geography of the body, over which particular glands may be said to rule or to possess a mandate. The hair of the head seems to be primarily under the control of the thyroid. Thus in cretins reconstructed by thyroid feeding, the straight, rather animal hair becomes lustrous and fine, silken and curly. In the thyroid deficiency of adults, a prominent phenomenon often is the falling out of the hair in handfuls. Baldness is frequently associated with a progressive decrease of the concentration of thyroid in the blood. At the same time, there tends to be a thinning of the eyebrows, especially of the outer third.

The hair of the face in males, and the other terminal hairs in both males and females, is regulated by the sex glands primarily. In the female, the ovary, that is to say, the interstitial cells of the ovary, inhibit the growth of hair upon the face. In destructive disease of the ovaries, as well as in other affections of it, hair in the form of moustache, beard and whiskers may appear in female. That is why in women after the grand sex change of life, the menopause, hair often grows in the typically male regions because of loss of the inhibiting influence of the ovarian internal secretion upon them. After castration of the ovaries, the same may result. Removal of the male sex glands, or disturbances of them, will interfere with the proper development of the normal facial hair. Of the hair of the chest, the abdomen and the back, the adrenals seem to be the controllers. Adrenal types have hairy chests in males, and hair on the back in females. They have also a good deal of hair upon the abdomen. The hair on the extremities varies a good deal with the pituitary. People with hair upon hands, arms and legs, alone, are generally pituitary, or have a striking pituitary streak in their make-up.

When the adrenals increase in size in childhood, a remarkable triad follows-general hairiness, adiposity and sexual precocity. One fact should be noted. When the adrenals evoke precocity, and an early awakening of the secondary sex characteristics, it is a masculine precocity, and an approximation to the masculine even in females. There is a definite trend toward an increase of the male in the individual's composition at the expense of the female. We shall have to consider this in greater detail when we analyze the internal secretion basis of masculinity and femininity. In general, the degree of general hairiness is an index to the amount of adrenal influence upon the organism. All the endocrines which affect the hair growth also act upon the sebaceous glands which oil the skin.

THE EYES

Eyes present clues to internal secretion constitutions dependent upon influences of architecture and function. The thyroid eye is typical. It is large, brilliant and protruding. The individual is "pop-eyed." On the other hand, subthyroidized eyes tend to be sunken and lustreless. The eyes of a pituitary type are either set markedly apart, or close together, with the hair at the root of the nose so prominent as to constitute a separate bridge known as the nasal brow. The size of the pupil, and its humidity, which have so much to do with the expression of the eye, vary directly with the activities of the driving and checking divisions of the vegetative system, and are a pretty good index as to which, at the time of observation, is predominant. When the check system is in control, the pupils are large and dilated. When its antagonist and rival, the drive system, is on top, the pupils are small and contracted. The reactions of the pupils when charged by strong emotion, like fear or anger, likewise turn upon the status of check or drive internal secretions in the economy of the organism at the time the exciting agent presents itself.

MUSCLES

It would seem, at first sight, that organs like muscles, mechanical instruments for the manipulation of the organism in space, would be more or less independent of the subtler processes of internal chemistry of the blood and tissues. But no assumption would be more beside the mark. Just as much as the bones and viscera, the teeth and the hair, they show grossly how they are being influenced by all the endocrine glands. So thyroid types generally have a skeleton sparsely covered with a muscular mantle. Pituitary types have large well-developed muscles. The pineal gland has some definite relation to muscle chemistry not yet probed. Thus, it has been shown that when the pineal has been completely destroyed prematurely by lime deposits in it, there is concomitant a wasting of muscles in places. This waste is sometimes replaced by fat. Pictures and images in wood and stone of these muscle freaks dating from the fifteenth, sixteenth, and seventeenth century are in existence. Then there is the extraordinary fatigability of the muscles which occurs in the thymus types, who nevertheless have large well-rounded muscles, a paradox of contradiction between anatomy and physiology. Such a type, for instance, may be picked out by a football coach for an important position in a line-up, simply on the tremendous impressiveness of the muscle make-up, only to see him bowled over and out in the first scrimmage. The tone of muscles, the quality of resisting firmness or yielding softness, is essentially determined by the adrenal glands, especially in time of stress and strain.

Brown-Séquard was the first to show that extracts of sex glands could increase the capacity for muscular work. Whether this was a direct effect upon the muscles, or indirect through the nerves or other endocrines, no one can say. Certainly the carriage of an individual, outer symptom of the inner tonus among his muscles and tendons, may be said to be as distinctively an endocrine affair as the color of his skin. And like its variations, variations of their tone, development, reactivity, fatigability, and endurance may be traced to corresponding states of overaction, or underaction, and odd combinations of the different hormones. Much remains to be learned about them and the manner of their control. Such an affliction as flatfoot, dependent upon a laxity of the ligaments in one who seems perfectly healthy and strong, may lead the analyst back to a thymus-centered personality. That is but one example.

Since, too, muscle attitudes, muscle tensions and muscle relaxations play so large a part in the production of fundamental mental states: the attitudes, moods, memories and will reactions, the vegetative apparatus enters, to play its part as a determinant.

SEX

Over no domain of the body have the endocrines a more absolute mandatory than over that of the whole complex of sex. Both as regards the primary reproductive organs, their size and shape, and the character of their implantation, malformations and anomalies, as well as the physical and mental traits lumped as the secondary sexual, puberty, maturity, and senility, voice changes and erotic trends, virility and femininity, the internal secretions are dictators at every step. So significant are these, that even a rough summary of the discoveries and the outlook in the field involves some consideration of the details.