The knowledge that the shape and action of a man's body as well as his mind depend on the internal secretions inspires the hope of the emergence of a hitherto inconceivable controlling power over human life in the future. For in the wake of chemical discovery there has always come chemical control. The nature of chemical research, the necessity for clear thinking, accurate measurement, and experience in the actual handling of materials, the fundamental tradition and technique of the science, have made and will make the practical applications about which we today may only speculate. What the study of the internal secretions suffers from, at the beginning of the third decade of the twentieth century, is insufficient appreciation of its meaning for mankind. It is true that there are thousands of workers scattered throughout the world contributing their mites to the general store. They increase yearly, almost daily, and their achievements, in spite of an uncritical enthusiasm in some quarters and a semi-charlatanism in others, have been and continue magnificent. But they are pecking at a mountain which requires organized, massive, engineering organization for its blasting.

The crying need is for an international institute, endowed and equipped for investigation upon the proper scale, with all the available appliances and methods already worked out and at hand. Such an institution would possess the right chemical laboratories for the making of blood analyses, metabolism examinations, and tests of endocrine functions. There would be X-ray machines and experts to radiograph the pituitary, pineal and thymus glands when possible. There would be psychologists to carry out intelligence tests, determine emotional reactions, and group mental aberrations, deficiencies and defectives. There would be statisticians, trained in biometrics, to criticize and compare data obtained. There would be anthropoligists to note and measure variations in angles and curves, ratios and quotients of the external conformation of the body. Internists would record the history and status of the organs and viscera. There would be librarians to collect, abstract and collate the vast, accumulating literature. In short, the mystery of personality, the most marvelous, complex, and variable process in the universe, would be attacked and at length penetrated systematically and persistently, with the ideal of absolute control of its composition as the goal in view.

The nature of the researches? They would be infinite in their variety and significance. Their practical by-products, dropped in the pursuit of knowledge by the scientist, as Atalanta's lover the golden apples in his race, to assuage the scent of the hard-headed business man, would be profitable enough for any country in peace or war, to pay for itself ten times over and at compound interest. A volume could be filled with suggestions for interesting and promising investigations. But we may glance at some of the immediately useful aspects that might exercise those concerned with the everyday life of men, women and children.

THE ENDOCRINE EPOCHS OF LIFE

There is no more famous classifications of the epochs of life that mark off the milestones of the individual's evolution than Shakespeare's Seven Ages. So different is he at those different stages of his development, so changed his body and mind that it has become a part of popular physiology that we are entirely made over every seven years, and that no cell in the organism lasts longer than that. The tradition certainly does not apply to the brain and nervous system, for the number of brain cells is fixed at birth, and cannot be increased, only decreased, because they are too highly specialized to reproduce themselves.

What transfigures the individual as the years go by is no simple wear and tear of the tissues, nor the replacement of old cells by new. It is the rearrangement of relationships among the ductless glands, the shifting of influences from the predominant to the subordinate, and vice versa, in the constellation of the internal secretions, that determines the unfolding of the personality. The transformations raise doubt sometimes as to the reality of personal identity. What actually happens in the changes from childhood to adolescence, from adolescence to maturity, and so on, is the sloughing of one internal glandular dominance for another.

Growth, as a general name for the mutations, the ensemble of somatic and psychic differentiation, from year to year, passes through five epochs that are standard for the normal. The normal is the being who harmonizes with his environment, and yet reacts with it because of recurring needs within him. His endocrine equation settles what is unique and different in him. But the gland which flourishes during the epoch as its time of triumph, when it has its day, determines what makes him like his fellows.

From this point of view it becomes permissible to speak of the five Endocrine Epochs. Similarities and resemblances of mind and body between people at a given period of life, childhood, youth, maturity must be put down to their common government by the salient endocrine of the epoch. So one may list:

Infancy as the epoch of the thymus
Childhood as the epoch of the pineal
Adolescence as the epoch of the gonads
Maturity as the epoch of whatever gland is left in control as the
result of the life struggle.
Senility as the epoch of general endocrine deficiency.

Infancy as the epoch of the thymus explains why, in any given geographic locality, the babies look alike and act alike. Specialists in the observation and treatment of infants have noted that not until after the second year is any tendency to differentiation discernible to any extent among them. It is only after the second year, or somewhere around that time, that the child begins to individuate, and distinct individual traits and a personality manifest their outlines. The thymus is the great inhibitor of all the glands of internal secretion. By its checking activity upon the other members of the endocrine system, the thyroid and pituitary in particular, it gives the baby time to grow in bulk, which is its chief business during the first two years of its existence. It quadruples its birth weight. The brain and nervous system complete their growth in mass by the end of the fourth year. Recall the experiments of Gudernatsch working with tadpoles, who showed that feeding with thymus produced giant tadpoles whose metamorphosis into frogs was inhibited, while feeding thyroid produced frogs the size of flies. Differentiation occurred without the preliminary increase in mass usual. As differentiation and bulk thus appear antagonistic, at least at the beginning of growth, the function of the thymus, at a maximum during infancy, seems then to be to restrain the differentiating endocrines, until sufficient material has been accumulated by the organism upon which the differentiating process may work.

After the second year, the thymus begins to shrink. That is to say, officially its involution begins. Careful dissection will demonstrate some thymus tissue even in a normal subject up to the fourteenth year. This refers to the average normal, for the large thymus may continue large and grow larger after the second year in the type of individual designated in a preceding chapter as the thymocentric.

If the thymus retrogresses after the second year, what takes its place as a brake upon the forward driving impulses of the other endocrines? We have every reason for assigning that rÔle to the pineal. It performs its service mainly, in all probability, by inhibiting the sex stimulating effect of light playing upon the skin. Since it is especially a sex gland inhibitor, the thyroid and pituitary become freer to exert their influences than under the thymus rÉgime. And so we find that it is after the second year that thyroid and pituitary tendencies manifest their effects. The Pineal Era, from the second to the tenth to fourteenth years, remains to be investigated from a number of viewpoints interesting to the parent, the educator, and the student of puericulture. Precocity is directly related to early involution of the pineal. For just as the thymus involutes at the second year, the pineal atrophies before the onset of adolescence.

Adolescence is the period of stress and strain throughout the somatic and psychic organism because of the volcanic upheavals in the sex glands. The history of the individual is dominated by them up to twenty-five or so, when maturity commences in the sense of a relative sex stability. They continue to exert a powerful pressure throughout maturity. But life episodes and crises, diseases, accidents, and struggles, experiences of pleasure and pain, as well as climatic factors, settle finally which endocrine or endocrines are left in control as a consequence of the series of reactions the period of maturity may be analyzed into.

THE INTERPRETATION OF SENILITY

Senility inevitably follows maturity, not as night follows day by a mathematical necessity, but because of the process of degeneration which ultimately overtakes all the glands of internal secretion, dominant as well as subordinate. Just why the degeneration must occur no one can say. Injury to the endocrine organs of one sort or another, ranging all the way from emotional exhaustion to bacterial infection, is the reason usually considered sufficient. Just why recuperation and regeneration do not preserve them in the elderly as they do in youth is a problem to be solved when we understand the laws of regeneration, at present almost totally beyond our control. Some say that it is a matter of the wear and tear of our blood vessels, those rubber-like tubes which transport food and drainage with nonchalant equanimity to all cells as long as they last. In the classic phrase: a man is as old as his arteries, ergo his ductless glands will be as old as their arteries. And the age of arteries is simply a matter of wear and tear, the resultant of the function which is universal among molecules. Arteriosclerosis, the hardening of arteries, might be the whole story.

But there are certain experiments and considerations which rather confute that easy explanation, or at least make clear that the mystery is not so simple. The work of Steinach, a Viennese investigator, has contributed most to the elucidation of the nonarterial factor in senility. No one has asserted more loudly the importance of the interstitial cells that fill in the spaces between the tubules of the testes in the male, and the follicles of the ovary in females. Rats have been his medium of study, for they are most easily procurable, live fastest, breed, and withstand experimental and operative procedures better than any other animal.

An old rat is like an old man in his dotage. His bald, shrivelled skin covers an emaciated body. His eyes are dimmed by cataracts and his breathing is labored and difficult because his heart muscle has lost its tone. Huddled in a corner, life to him has become concentrated into the desire for a little food, and immobility. If now, something is done to his sex apparatus, a marvelous transformation may be effected. That something no one could predict. It consists in slitting the genital duct, which leads from the germinal cells to the exterior. After the operation, the germinal cells, which grow into the spermatozoa, atrophy and disappear, since they can no longer function. As if released from some restraint, the interstitial cells, however, multiply enormously. With their multiplication, the miracle of rejuvenation is performed.

After some weeks the sluggish currents of being in the rat, which had slowed down as a preliminary to stopping altogether, flow fast and furious. Waves of new chemical substances inundate his cells. And they respond like the fields that border the Nile after the annual flood. All his tissues, skin, muscle, nerve, even bone, are restored. A vitality is created which makes him bound and dart like a youth of his species. In due time, though, senility returns. It is as if a storage battery, recharged, runs down and becomes dead again. Slitting the genital duct of the other testis, causing its interstitial cells to hypertrophy and multiply, repeats the effects of the first experiment. The organism responds again to the new waves of vitality that vibrate through it. That it is recharged is demonstrated again by a revival of sex appetite and sex activity. The female which had become an object of indifference is reinstated as a creature to be sought and pursued. The second period ends in its turn. And now entirely new interstitial glands, in the form of fresh testes removed from a young animal, are transplanted into the body of the old rat. Once more youth returns. But now it burns itself more quickly than even before. An acute exhaustion of the mind appears first. Then all the other phenomena of old age steal back upon the old rat, and senility, firmly established in the saddle, rides him to the end.

THE POSSIBILITIES OF REJUVENATION

Whatever other deductions may be extracted from these experiments, they prove beyond a doubt the existence of an endocrine factor in the process of aging, as well as an arterial. They also demonstrate that the internal secretion of the sex glands, well advertised as it has been as the Elixir of Youth that Ponce de Leon, and Brown-SÉquard with so many others, pursued in vain, is not the whole story. For if it was, the duration of the new youth should be another span of life, whereas in actuality it is only a fraction of that time. This fact, together with a number of others, make clear that while the gonads may be the jeune premier of the drama, the vitality of the plot depends upon the other endocrines. Since old age is an exhaustion, permanent and irreparable of all the members of the ductless gland directorate, the reason becomes clear for the temporary quality of the rejuvenation effected by the procedures of Steinach.

Practically, then, the question at once arises: which of the glands in particular are involved? There is first that ubiquitous agent in the system, the thyroid. Chemical analysis of it has shown that the iodine content decreases with the age of the individual, and becomes specially low after forty. It is after the menopause in women that myxedema, the disease of complete degeneration of the thyroid, and of the physical and mental faculties, is most frequent. The thyroid of old people exhibits, in varying degrees, signs of a similar degeneration. Thyroid feeding, properly controlled, will clear up certain of the deteriorations of mind and body observable in the aged. The grossness of the features lessens, a number of the pains go, muscular endurance increases, memory and intelligence do not remind one so forcibly of the old dotard in his second childhood. Of course the improvement at present achievable is only relative. But in the prematurely aging, decay invading a half accomplished maturity, marvels have been achieved at times with feeding of the gland.

The pituitary, too, begins to retrogress after the period of maturity. And an early retrogression means a short maturity. In women, the onset of an obesity, and coincidently, of a lazy and dull morale, coincides with this declension of the pituitary powers. All the glands of internal secretion, in fact, shrink and shrivel as old age advances. Only, as in other relationships, the predominating endocrine stamps its signature more visibly upon the documents of decadence than the others. Pituitary types, as said, get fat and slow, thyroidal become bulky and stupid or thin and sour, the adrenal dark, shrunken and forever tired of life. So type emerges, even in all-around glandular deficiency.

The problem of rejuvenation is the problem of recharging, or replacing all of the glands of internal secretion, at least the most important, the thyroid, the pituitary and the adrenals, as well as the gonads. Longevity is perhaps largely a matter of preventing, or postponing their wane. Beside, there is the prophylaxis of bacterial infections, and their all embracing corrosions—which, too, have an endocrine aspect.

Persistence of youth or juvenility may be manufactured by nature in two ways. There may be a persistence of early glandular predominances. We have seen what happens to the thymocentric. That a pineal-centered juvenile or infantile type exists may be safely predicted. Nature's only other mode of securing perpetual youth seems to be by prolonging the time allotted to the sex gland crescendo.

As for the golden age of maturity itself, what humdrum people and poets have despised as middle age, the margin of reserve of the ruling hormone is a quantity almost malleable in our hands, but still to be regarded with respect as a hard cold proposition by the physiologist. In general, the continuance of any stage of development means the maintaining of the glandular administration peculiar to it. So the chubby debonair irresponsible whom nothing can touch is happy in the possession of a pineal uncorrupted by the years, while the genius who can turn out his best work at sixty-five must thank his pituitary for standing by him to the end.

THE SCIENCE OF PUERICULTURE

There is a specialty now growing in the womb of science which in its own good time will come to fruition as the study of the child's needs or puericulture. Even today there exists a scientific basis for the formulation of the principles upon which every child should be brought up. Though we have had marvelous results from the campaigns to lower infantile mortality, most of what has been done has been medical in its interest, and so largely negative in its accomplishments. The removal of the causes of evil no doubt gives the good its opportunity. But how to raise a child, endowed with satisfactory ancestral stuff, as a Grade A normal or supernormal, still remains to be erected into an exact science.

A number of attempts have been abortive in this field. Why they have failed to arouse the ardor of the parent has puzzled some of the pioneers. Child-culture as the foundation of all systems of education has continued more or less of a hope rather than an achievement because of a lack of appreciation of the different constitutional varieties of children. A certain amount of attention has been lavished upon children needing special attention, those mainly suffering from insufficient development of one sort or another. In the last decade or so, an endeavour to focus upon the exceptional child, exceptional in intelligence or some special creative endowment, has started an interesting movement. All of them have suffered from the fallacies and troubles of the pure psychologist who would handle mind as an entity in a vacuum.

A realization of the different physical and psychic educational needs of various children will arrive only when we see them as built differently. Just as shoddy and silk, cotton and wool, alone or in combination, all possess different qualities as wearing material, so different children have varying capacities for the wear and tear of education. The endocrine classification of the human race, applied to children, will here yield a harvest to the educator and to the country. Nothing is more evident than the diversified nature of the needs of the various internal secretion types, once they are realized as such.

The history of a thymocentric type, for instance, is predictable from the very first few months of his life. Difficulties in feeding, in habit formation and adaptation, in the reaction to infections, in social play and so on, one may expect for him. The course of events for the other endocrine types also follow laws of their own. It will be above all in the understanding of children, their make-up, reactions and powers, that the biologist will achieve some of his finest triumphs.

The educator will have to take account of the state of the pituitary in estimating the normal intelligence, or influencing the abnormal or subnormal intelligence. As well will he have to consider the thyroid in the child whose conduct is refractory, even though his proficiency in his studies is excellent. And the condition of the adrenal will be ascertained in the types that tire easily, and that seem unable to make the effort necessary or desirable. Periodic seasonal and critical fluctuations in the equilibrium among the hormones will have to be taken into account in the explanation of what have hitherto been put down to laziness, naughtiness, stupidity, or obstinacy.

A child's capacity for education, essentially its capacity for the highest and most productive kind of life, is limited by inherent factors. These factors are two: the quality of the nerve tissue, its ability to make a number of associations, and the quantity of the internal secretions, measured by the maximum obtainable in a given situation. These inherent factors explain, too, why children born and bred in virtually the same environment show the most extreme differences in educability. That the differences are inherited was made evident by Galton's finding that the chance of the son of an eminent man exhibiting eminent ability was 500 times as great as that of the son of a man taken at random.

Every baby, then, is born with a combination of nerve cells and ductless glands which determine its capacity for mental development, that might never be realized, but could never be exceeded. If, in any family, minor differences in educability are observed, they can be put down to disturbance of these two factors occurring after the fertilized germ cell had started to divide and reproduce itself. But any marked falling off in either the nervous or endocrine factors has to be considered pathologic, due to an impairment of them by adverse environment.

Recent studies have amply established that the proportion of certifiable mental defectives, and of a much larger class, the subnormal but not certifiable class, is progressing by leaps and bounds. It is perhaps the most absurd frailty of our present system of education that it takes almost no account of innate differences in educability. To spend money upon the teaching of these children along lines where they are unteachable is not only waste pure and simple, but crime, for it deprives the educables of their just due.

These, of course, are the crude and simple lines upon which the finer and more complex evolution of the endocrine problems of the school child will build. The fine art of education itself is crude and gross and simple compared with what it might be, even as a beginning. The science of education has yet to begin, as the offspring of that science of the future, to which knowledge of the internal secretions will contribute no little, the science of puericulture.

VOCATIONAL EDUCATION

It is difficult, indeed, to avoid becoming merely enthusiastic upon the possibilities of the applications of the endocrines to the educational domain. Happiness for the average individual consists of a double success—success in his vocation (chosen or forced upon him) and success in his sex life. A certain hue and cry has been raised in the last few years concerning the vast and overwhelming importance of sex in the happiness and even in the successes of a man's everyday life. And no doubt there is a relation. Sublimation plays its part in the explanation of vocational idiosyncrasies. The fact, however, that perfect success in sex may occur with absolute failure in the career, however, splits the problem for good into its realities: a physiologic aspect as well as a psychologic.

So, as school education will have to take serious account of endocrine anomalies and possibilities, will the institution which selects and trains for a career. Vocational misfits have aroused the ardor of our efficiency experts. And again, the sweeping psychological attack has beaten its head against the stonewall of ignorance of constitutional predispositions and tendencies of material. The attempt to erect psychologic types for vocational selections could never make much headway because it could only flounder in a swamp of metaphors, product of the vices of its methods. Not that anyone would wish to discard at all the psychologic mode of approach. But no science, in the sense of accurate examination, was possible, in the matter of classification for vocation, without the insight into the physiology of the candidate that the analysis of his endocrine formula will provide.

One need not dilate upon the value of such an examination. Civilization has not yet learned how to pick its personnel. And so artists and scientists, philosophers and politicians, financiers and religious leaders, arise and survive by the operation of the laws of probabilities and chances, rather than by any intelligent selection and cultivation of material. The case, indeed, is simply a subdivision of the vast subject: haphazard muddle in the conduct of life. A cry has been raised for the superman, and a cry has been raised for a method of anthropometry. For the lack of these two, it has been said, all governments have been doomed to defeat. The study of the endocrines will by no means supply a panacea. But as it will furnish a means of approach to the determination of how men and women are built, and why they are built differently, no one can gainsay the tremendous advantages to the nation that will proceed to classify its population accordingly, and know its strength and weakness in terms of the actual generators of success and failure.

Suggestions have been offered in the preceding pages of concrete applications of endocrine knowledge to the understanding of behaviour, of the genius and commonplace, criminal and Puritan. And in the chapter on historic personages, we tracked some of the story in detail. This vein when explored will quarry untold riches. It has been observed that financiers of mark, like great musicians, are special pituitary types. Also that the financiers are voracious meat eaters and the musicians inordinately fond of sweets. Differences in anterior and posterior predominances might account for this. That we are playing here with no phantasy is proven by the fact that we can effect changes of tastes as well as of intellectual direction by appropriate feeding of various glandular extracts. Just as much, indeed, as we can influence sex susceptibility, and the reaction to sex stimulation, by the artificial introduction from without of the proper hormones.

FATIGUE AND INDUSTRY

In industry, business and profession, the biologist will come more and more to be called as consultant. Labor unions as well as the large employers of labor, and their employment managers have given much thought to the problem of fatigue. Just what fatigue is, why different individuals tire at different rates, why some are constructed for monotonous routine while others must have constant variety and change, the relation to accidents and to quantity output, are a few of the major lines of inquiry upon which the endocrines obviously have a large bearing. To the employment manager, labor turnover and the selection of personnel are adjacent fields of research.

Fatigue as an endocrine deficiency—a depressed state of one or more of the glands of internal secretion, abolished when its normal functioning is restored—is a general principle from which departures of exploration of sub-problems will proceed. An endocrine organ will secrete at a certain rate. When it is stimulated excessively, it will eject extra amounts of its secretion. How long the period of excessive stimulation may last must depend upon the secretion potential or margin of reserve of the cells, varying from organ to organ, and from individual to individual. After that, exhaustion and failure follows, with the onset of the symptoms of fatigue.

A pretty demonstration of this process has been worked out in the electrical stimulation of muscle. If a muscle, say the biceps, is irritated by an electric current, it will contract. As the strength of the current is increased, the degree of contraction becomes greater. A sort of stepladder effect of increasing contractions may be thus obtained. After a time, the electric shocks cannot cause a greater contraction, but only a lesser. And if continued, the muscle will cease to function because of fatigue. If now, when the muscle begins to lag in its response, and its contractions to decrease, one injects into a vein extracts of thyroid, parathyroid, or adrenal glands, they will immediately reinvigorate the failing contractions. The injections must be made before the fatigue is carried to the point of absolute exhaustion. It follows that these glands normally pour into the circulation substances which counteract the effect of fatigue substances, and in fact make possible muscular recuperation from fatigue throughout the day as well as in emergencies and crises.

Fatigue, conventionally recognized, is something acute and urgent. As such it means a violent draining of the endocrine wells. But there is also a chronic fatigue, which has been dignified with the name of Fatigue Disease. Bernard Shaw once asked for someone to tell him the name of the germ causing the symptoms of overwork. That being impossible, he will have to be satisfied with the answer that it is not a germ, but an internal secretion, or rather a defect of internal secretion that is the cause.

Whether or not the adrenals have been damaged by past experiences, and upon their capacity to respond to the necessities of an occasion, fatigue reactions primarily depend. A quotation from Sir James MacKenzie, most distinguished of modern English students of medicine, summarizes the matter neatly. "Abelous, and Langlois and Albanese have studied the relation of the adrenal bodies to fatigue…. They infer that the muscular weakness following removal of the adrenals is due to toxic substances. In view of our present knowledge of the physiological action of adrenaline in its various forms, it seems more probable that the weakness is to be explained by the absence of the normal tone producing internal secretions of the bodies in question." In other words, the adrenals regulate muscle tone. They produce nature's tonics for weary tissues. The chronic lassitude of thousands of our generation, suffering from "that tired feeling," may be put down to chronic adrenal insufficiency.

It requires no superlative imagination to see that an adrenal poor subject does not belong upon a job that involves muscle stress over a long period, or indeed fatiguing conditions of any sort. Nor that a thyroid poor individual is not the best choice for a position that demands a keen, alert body and mind. In the selection of executives, the nature and stamina of the pituitary will undoubtedly be taken very seriously in the near future.

A certain hocus-pocus concerning character reading, a perverted revival of the ancient phrenology and physiognomy, has invaded the employment territory in America as the newest charlatanism. The study of the internal secretions, including blood and X-ray examinations, will surely assist the demand for a truly scientific estimate of constitution and character that can be relied upon in the classification and distribution of personnel.

THE PROSPECTS FOR PUBLIC HEALTH

By their effects upon the endocrines, public health influences like food, clothing, sleep and overpressure and last but not least, disease, the so-called diseases of childhood, possess a tremendous importance in limiting the output of the educable. They act to subtract from and so to lower the rating, the capacity of the germ-plasm. Most material and vital of these influences are the common diseases of children, for they strike directly at the glands of internal secretion.

Measles, scarlet fever, diphtheria, mumps, and the others have long been accepted as providential visitations for sins known or unknown. That children had to have them and were better off when they had them has become part of the tradition of the laity, fostered by the lazy ignorance of previous medical generations. But today we are beginning to ask ourselves why children must have these endemic infections of their age. The pathologist goes farther and asks the reason for certain apparent immunities. He asks why the little boy who sleeps with his brother sick with scarlet fever does not contract the disease, even though not protected by a previous attack.

Determining why susceptibility to a special disease in a particular case exists will constitute the greatest line of advance for the understanding and prevention of disease, and so the perfection of public health. In the last influenza epidemic countless physicians were puzzled by the spectacle of men and women in the pink of condition carried off in twenty-four hours while puny associates were either passed over, or pooh-poohed their colds. Pathologists have spent their energies fruitfully upon the infectious causes of disease, the microbes and parasites especially. But now, having solved most of those problems, the vital question of why an organism permits itself to be attacked is pushing itself to the front. Why a peculiar ailment selects its victim, why the bacillus finds a fertile soil, is the neglected problem, which must be solved before the abolition of disease and its carriers will be remotely conceivable.

Long ago, Hippocrates, revered founder of the art of medicine, recognized that there was a specific affinity of disease for individuals with more or less the same characteristic somatic and psychic traits and trends. Tuberculosis, for instance, was noted for its frequency in long-skeletoned, thin persons, remarkably optimistic. And the plethoric, choleric nature of the sufferer from gout has become proverbial. Before the era of the great bacteriologic discoveries of the eighties and nineties, the concordance of esoteric racial and personal markings was a great help in diagnosis to the physician. For he realized, though he sometimes credited it to his clinical intuition, that it was a certain type of personality that was liable to the specific disease.

But personality and its reactions, normal and abnormal, are determined by the endocrines. So we should find that particular infections run with special internal glandular predominances. For the picture presented by an infection, temperature, rash, prostration, are the details of the general reaction of the organism in the face of a new situation, the presence of a powerful, destructive invader. Information has accumulated that the invader is powerful and destructive, as well as selective, because of endocrine deficiency of one sort or another in the body it has attacked. Work of a number of investigators has indicated that an individual's susceptibility or its reverse, resistance, is intimately subjected to the derangements or harmonies of the endocrine system.

Comparison of the endocrine type and the disease assaulting has yielded an even more interesting principle. Knowing the state of the internal secretion reservoirs enables us to predict the liability to certain of these infections of childhood. Diphtheria has been found to occur most virulently among adrenal poor individuals. Moreover, they are left poorer in adrenal afterwards. It follows that they would be assisted by the feeding of adrenal. Mumps is a sickness that sometimes permanently injures the gonads: the testes or ovaries. The thyroid dominant, whose system is rich in thyroid, will rarely suffer from any of the common diseases of children—if at all, from measles. Op the other hand, those who have every infection of the period, and who, as their mothers say, seem to get everything, are those whose system is thyroid poor. Thyroid poverty is a splendid enticement to the universal microbe. The thymocentric stands all diseases poorly. The pituitary type is more liable to epidemic meningitis and infantile paralysis, typhoid and scarlet fever.

The public health officer of the future will be armed with a new weapon in his fight against the spread of an epidemic. He will be able to classify the endocrine traits of the population exposed, and to advise a course of glandular feeding for the types specially liable. The Schick test for diphtheria susceptibility is an illustration of one method of approach to the problem of the epidemiologist in settling who needs protection. The endocrines will assist him in the great body of diseases for which no immunity test is at hand. Should another influenza epidemic come along, for instance, the proper handling, from the endocrine standpoint, of the thymocentrics and the related adrenocentrics would help considerably in lowering the mortality.

Endocrine types have other tendencies, which when studied and controlled, will decimate the great assassins of middle age: heart disease and kidney disease, with accompanying degenerations of the blood vessels and circulation. The adrenocentric tends to get up a hyperacidity of the stomach and a high blood pressure, besides certain forms of diseases of the lungs. The thyrocentric is predisposed to heart disease, as well as intestinal disturbances. The pituitocentric is liable to periodic and cyclic upsets in his health.

Narcotism, the craving for narcotic or stimulant drugs, and its subvariety, alcoholism, has been found most often among the thymocentrics. Any type of endocrine inferiority, interfering with success in life, may lead to the habit of drug addiction as one way out. But the blood and tissues of the thymocentric appear to become habituated to the narcotic stimulant more easily than the other types, and so to demand it with a physical imperative comparable to the food or sex urge. Among artists, philosophers and statesmen, on the other hand, actively productive and so contrasted with criminals and degenerates drug addiction has frequently been a mode of endocrine compensation. That is, the drug produced temporarily the effects of the internal secretion lacking or insufficient. Thus the effects of cocaine may be compared with the effects of thyroid. But while there is a normal mechanism for thyroid detoxication, the cocaine or heroin derivatives mark the tissues permanently with their scars and deform the personality.

THE HYGIENE OF THE INTERNAL SECRETIONS

All these protean expressions of endocrine determination may now begin to be looked upon with the hopeful and optimistic attitude of him who understands cause and effect and can control. The advances made in the last ten years in the practical manipulation of the ductless glands from without, the introduction of glandular extracts by feeding or injection, and the modification of their structure and function by surgery, the X-ray and radium, and other procedures, enable us to regard more confidently the problems hitherto accepted as the insoluble and intricate handiwork of Fate. Fate may have woven the patterns of our being. But as we commence to probe the machinery and to examine the looms more carefully, we begin to understand why the wheels creak, and why there are seconds and odd lots in the product as well as the rare and precious firsts. Moreover, we are learning how to handle the machinery ourselves. The abdication of Fate can therefore be confidently expected in due time.

However, we have yet to begin, and we can begin with prevention. The theory of Adler, that some organ inferiority is responsible for much unhappiness in life has received much advertisement in conjunction with the doctrines of the Freudians. It is a theory of little scope when applied to the eyes, ears, heart and so on because only a small minority of the cases are of that kind. But as we have seen, a deficiency of an internal secretion, an endocrine inferiority, reverberates throughout all the cells. Not only the mind, but all of the members of the organism must strain and co-operate to make up for the break in the balance.

Endocrine inferiority is indeed the most frequent organic inferiority. And we may explain a number of mental types upon that basis. Thus the inferior gonado-centric, who has something wrong with his reproductive organs, will evolve in one of two directions. If his adrenal and thyroid are of poor quality, he will become the secluded introvert, shut off from the interests of normal life. He will enter the borderland of insanity if pituitary difficulties supervenes. If, on the contrary, the adrenal, thyroid and pituitary are present in a certain proportion, he will become the active, aggressive, never-resting, keen, and relentless fanatic reformer. A woman who is gonad deficient with a superior adrenal will suffer from virilism and specialize in the extreme tactics and mythology of the feminist movement. A number of life reactions are classifiable as the strivings of endocrine inferior individuals to overcome their sense of inferiority. The unconscious vegetative system and the system of consciousness are both modified by the weakness of a link in the glandular chain.

What, therefore, is to be recommended in the prophylaxis of the natural deterioration of the wells of life, the ductless glands? For even if we may be able to replenish them when they dry up, would it not be better to delay their dessication? The hormones reply to every call of life and respond in every reaction. The normal constructive process of their cells remanufactures what has been lost, and the original capacity to respond is restored. If, though, the rate of destruction and loss outruns the rate of repair and construction, they will be permanently damaged. This is what occurs in shock, serious, severe accidents and injuries, prolonged infections and diseases, profound continued emotions, and the wear and tear of overwork. The prevention of these excessive fatigues of the endocrine system in one or all of its parts, and especially the prevention and enfeeblement of the diseases of children which injure them at a period when they are most sensitive to injury, is the task of the endocrine hygienist. Periodic examinations, to check up the balance sheets of the hormone factories and to measure the amount of their damage by means of blood analyses, will provide the most valuable method in the campaign to lengthen the productive and enjoying span of life.

THE TREATMENT OF CRIME

Endocrine hygiene will discover no wider or more fruitful area for exploration and control than that of crime. For more than a generation there have been attempts at a criminology, and a new understanding and control of crime. In the United States a concomitant sentimentalism has concocted measures like the honor system which, naturally failing of their purpose, have undermined confidence in the idea of scientific diagnosis and treatment of crime. As someone has noted, to ask a criminal to promise not to misbehave, when discharged from prison, is like asking a typhoid fever patient to promise not to have a temperature above ninety-nine degrees the next morning. For a large proportion of criminals—the percentage has yet to be determined, although the most recent police commissioner of Chicago has estimated it at ninety per cent—punishment for a period of time and then letting him go free is like imprisoning a diphtheria carrier for a while and then permitting him to commingle with his fellows and spread the germ of diphtheria.

Of course, the doctrine of responsibility is all tangled up with our attitude towards and treatment of crime. Though clear thought makes mandatory the recognition of a universal cause and effect law, practical common sense has defined free will. Consent or the withholding of consent to a given course of action has been the criterion of responsibility.

In practice, the limitation of responsibility will depend upon the insertion of extraneous factors into the formula of consent. The pragmatic test has been and will be the probability that the correction of the somatic or psychic condition would have prevented or will prevent the consent to the crime. As long as no such condition will be demonstrable, society for its own protection will have to confine the unfortunate individual.

The character of the confinement, its duration, and the uses to which it will be put should be dominated by the idea of discovering the unknown criminal predisposition. If crime is an abnormality scientifically studiable and controllable like measles, court procedure and prison management will have to be transformed radically. There is scattered throughout the world now a group of people who are applying medical methods to the diagnosis and treatment of crime. They are the pioneers who will be remembered in history as the compeers of those who transformed the attitudes toward insanity and its therapy. The insane were once condemned and handled as criminals are in most civilized countries yet. The criminologic laboratory as an adjunct to the court of justice, like that associated with the court of Chief Justice Olson in Chicago, remains to be universalized. What contribution to a more rational treatment of the criminal will the study of the internal secretions make?

It has been shown that the greater number of convicts are mentally and morally subnormal. To explain the subnormality, the criminologist has conducted and will continue to conduct investigations into the heredity and early environment of the criminal, his education and occupation, the social and religious influences to which he was subjected, and the intelligence test quotient. The conditioning of the vegetative system and the endocrine status of the prisoner, however, will without a doubt come to occupy the leading positions in any interpretation of crime in the future.

Introspective observation of pre-criminal states of mind by so-called normal persons reveals that in many of them there is an impairment of reason and will power, in others an exaltation amounting almost to hysteria. What are these but endocrine states of the cells, experimentally reproducible by increasing or decreasing the influence of the thyroid, the adrenals, the pituitary? Crimes of passion may be traced in no small part to disturbances of the thyroid. A psychologic examiner of a Pittsburgh court, interested in the subject, has found an enlarged thyroid in over ninety per cent of delinquent girls. Similarly, crimes of violence may be ascribed to a profound break in the adrenal equilibrium. Criminal tendencies in women during menstruation and pregnancy, periods of deep-seated mutation in the internal glandular system, have long been noted. A kleptomania, uncontrollable desire to steal, confined to the duration of pregnancy alone, has been described. We have seen how the thymocentric, especially if he possesses a small bony case for his pituitary, is predisposed to crime. A recent study of twenty murderers in the State of West Virginia showed them all to have a persistent thymus and the thymocentric constitution. A study of the recidivists, those who return for second and third offences, in one institution, disclosed that a large majority had a subnormal temperature and an increased heart and breathing rate. These are endocrine-controlled functions. Conduct, normal or abnormal, being the resultant of the conflict of conscious and subconscious impulses and inhibitions, the internal secretions as controllers of the susceptibility of the brain cells to impulses and inhibitions, must be held accountable for a portion at least of the chemical reactions behind crime.

It is possible, by X-ray treatment of the thymus, to cause it to shrink to more normal proportions. It is possible, by feeding various glandular extracts, to correct deficiencies or excesses of their function, and so to remedy the underlying basis for a criminal career. Here and there work of this kind has been successfully carried out in selected instances. What a suitable drive upon the whole matter would yield in happiness to the individual and dollars and cents to society, time alone will show.