Senescence, the Last Half of Life

by G. Stanley Hall

Now, secretions of the thyroid gland check this aggression of the lower upon the higher cells, as is shown in the studies of cretinism, which is in so many respects nothing but premature old age brought on because the thyroid fluid, the special function of which was to retard this process, was not supplied; and when it fails, old age comes on precipitately and even children often look and act much like prematurely old men and women. On the other hand, the Metchnikoff ferments of the large intestine weaken the higher cells and leave them with less power of resistance, so that they become more easily the prey of the lower cells of the connective tissue. The enemy, however, for the endocrinologist is not primarily a microbe entering from without but a more formidable and subtle foe that springs up within. The difficulty in meeting the situation is immensely enhanced by the fact that the cells of the conjunctive tissue are not only useful but indispensable for the work and the development of every organ at first and continue to be so as long as they do not transcend this their original function and trespass outside it. The white corpuscles, although the source of the connective tissue cells, are themselves our chief defenders. It is they who attack and devour invading microbes but they consume not only these but also higher cells that have, by the action of microbes or otherwise, become debilitated. They are, however, on the whole, so serviceable that we cannot intervene against them but only against our more dangerous and insidious enemy, the conjunctive tissue cells.

Not only the thyroid but yet more the tiny parathyroid glands secrete a fluid, the absence of which brings convulsions and death. A knowledge of the function of these glands, no larger than a pinhead, as well as that of the adrenals or of the far more complex pituitary body (hypophysis), each lobe of which plays its own particular rôle, has been nothing less than revolutionary. The effects due either to excess or deficit of the secretion of these glands, which have been studied experimentally in animals and observed in man, show that they have great power even to arrest or accelerate growth itself. It is they that do much to keep us young or make us old. In a sense they furnish the power that makes about all the organs do their work efficiently, as an electric current from a battery may start, or its absence stop, the most diverse kinds of electric machinery. Thus glands have come to play a great rôle in physiology, medicine, and even psychology, and their activities have come to be recognized in very many phenomena both of health and disease, which till recent years no one had suspected. Some of these glands contain a relatively small number of cells but do a vast amount of work and manufacture fluids that no chemist can duplicate and that seem almost magic in their effects. We owe to them growth, health, and vitality.

Most important of all, and the chief source of human energy in man, are the sex glands, which distribute energy to all the sixty trillion cells of the body, making each carry out the function assigned it. Voronoff made personal studies of eunuchs in the East and among the many traits so often mentioned he finds them not only arrested along various lines of bodily and psychic growth but short-lived and perhaps old before they are forty. They are often selfish and crafty. Sex glands stimulate not merely amorousness but all kinds of cerebral and muscular energy, pouring into the blood a species of vital fluid, and give a sense of vigor and well-being and plenitude of life, which later vanish when their source begins to run dry in age. Can this wonderful source of human energy be placed, in any sense, in man’s control? It has already been proven that trituration of the sex glands does not produce its entire product and particularly lacks the active element. Moreover, all preparations of this liquid change very rapidly and may even become toxic. This method has passed beyond the stage of ingestion in the stomach or subcutaneous ingestions.

Voronoff undertook to graft young sex glands themselves into bodies older than those from which they came and if they lived and throve in the body of the host, the product they secreted would be complete and also vital. He says of the testes: “To graft this gland is to participate at first hand in the work of creation, to imitate nature in the procedures which she has elaborated in order to secure the harmonious functioning of our body”[190] (p. 65). He published his first results in 1912. He then showed a lamb born of an ewe whose ovaries he had removed, replacing them with the ovaries of her younger sister. His most important paper was read in October, 1919, on “Testicular Grafts.” He had been experimenting on flocks of sheep and goats, grafting the whole gland in twenty-five, large fragments in fifty-eight, and small ones in thirty-seven individuals. Transplantation was effected subcutaneously sixty-five times, in the scrotum itself thirty-two times, and twenty-three times in the peritoneum. Anastomosis did not follow; nor was it necessary. Testicular tissue, he thinks, has remarkable aptitude for transplantation and a microscopist, M. Retterer, shows us with abundant illustrations just what takes place. The nutrition of the small fragments was more easily assured than that of the large fragments or the whole. Sometimes where sex power is restored in old animals so that they bear young, the parental instinct seems weakened, but the rejuvenation effects of this process, as his many photographs show, are marked. The old and debilitated animals become well, lively, vigorous, and belligerent.

Voronoff is very candid in admitting that his interest and enthusiasm may cause him unconsciously to overestimate the rejuvenating effects of his grafts, and he also admits that he does not yet know how long the beneficial effects will last. That they have done so for two or even three years is beyond question. He is conscious of the incredulity of biological experts but reminds them that a society of physicists, when first shown the phonograph, insisted that it was ventriloquism. He calls attention to the great difficulties in his field, due not only to prejudice but to laws that forbid the taking of organs of healthy men killed by accident. He does not expect surgery will ever remove glands or even portions of them from the living young to revitalize the old, in human subjects, although he thinks that perhaps “the restoration of the vital energy and the productive power of Pasteur may well be worth the slight pain inflicted on the robust porter.” Most men, however, would prefer to lose an eye rather than one of these glands, as the price proposed by a few who offered themselves for this purpose shows.

Voronoff sees a great future possible for glandular transplantation and grafting between men and animals but shows that this can never be very effective for man save with apes, to whom he is so much more closely related, even in the makeup and properties of his blood, than to any other species. Thus the organ of an ape transplanted to man will find there nutritive and other conditions very like those it was used to. Surgery has done much and wonderful grafting in the war, even of bones, and now man, “the talented ape,” as Huxley called him, is recognizing his simian ancestry in a new way. A fibula congenitally missing in a child was successfully transplanted from an ape, and the radiogram showed complete intussusception, no absorption, and it functioned well. Voronoff transplanted the thyroid gland of an ape into the neck of a boy of fourteen, who was lapsing to cretinism, with remarkable results which he describes in detail and with photographs, although the ape from which the thyroid was taken died. The transplanted gland was not merely tolerated and then expelled as a foreign body or resorbed but the graft seemed to really take and its effects to be permanent and not temporary, like those due to the ingestion of thyroid tablets. The boy changed in his habits, his school work improved remarkably, and the last heard from him was that he was a soldier at the front. Here the beneficial effects were marked and traced for six years and seemed to promise permanence. Other grafts from apes for cretinism have been made, but because chimpanzees, which are best for this purpose, are very hard to procure in sufficient numbers, this process must always be limited. Voronoff has, however, made no grafts, even of thyroids, from parent to child save in one case; and here, although the young imbecile was nearly twenty when the operation was performed, marked improvement took place. The ape is, in a sense, however, superior to man, as represented by the quality of these organs, owing perhaps to a more robust physical constitution; or it may be due to the fact that with the first boy the graft was from a young ape and the latter from his mature mother.

For woman, for whom old age has perhaps even greater terrors than for man, such restoration has not yet been made. Indeed, ovariotomy has less effects upon young women than does castration upon man, so that here we face a new problem that cannot yet be solved. The problem now is whether we can generalize yet from these special studies, including bone grafting and the surgery of transplantation of other organs. Kidney grafting has been successful as yet only on cats and dogs but opotherapy or the administration of glandular extracts of animals when our own fail is in its infancy, although it does seem to give promise of deferring death and increasing the vigor of human life. Indeed, he thinks that the renewal of worn-out glandular mechanisms by grafting may even become a commonplace. The vital fluid supplied by these organs “restores energy in all cells and spreads happiness and a feeling of well-being and the plenitude of life throughout our organism.” The idea of controlling this marvelous force and placing it at our service when the natural sources of our energy begin to dry up with the advance of age has long haunted the minds of investigators, and Paul Bert and Ollier decades ago dreamed of a day when old organs might be set aside like worn-out clothes and replaced by new ones. “Several of these animals operated upon have exceeded the age limit which animals of their species generally attain and, instead of showing signs of decrepitude and senility, they give promise of astonishing vigor.”

Louis Berman, M.D.,[191] tells us that infancy is the epoch of the thymus, childhood of the pineal, adolescence of whatever gland is left in control as the result of the life struggle, and senility is the epoch of gradual endocrine insufficiency. The discovery of the effects of endocrine secretions he compares with that of radium and thinks that by control of this function we may be able to modify the rigidity of Weismann’s dogma and affect heredity itself. He draws a very long bow and even attempts to characterize important personages and races according to the predominance of thyroid, pituitary, or adrenal secretions and sees here the fundamental determinants of human character and conduct. Well informed and expert as he is in this field, his views, though bold and interesting, are, it must be admitted, more or less speculative in the present state of our knowledge, and he devotes little consideration to old age or to the methods of deferring it.

If we conceive life as the sum total of all the forces that resist death and death in its essence as the queller of life, it is to biology, not to theology or philosophy, that we must look for our most authoritative and normative ideas of both life and death. We must examine not only the now very copious data that this science already supplies but also the instrument that defines, delivers, and interprets them, namely, the mind, so that psychology must henceforth have a place here second only to biology in formulating conclusions. Now, psychology teaches not only that there are certain determining tendencies that always, in part at least below the threshold of consciousness, direct the course of thought, slowly build up centers of apperception and interest, and that must always be reckoned with sooner or later not only in the treatment of any subject in which their action is involved but also when almost any scientific laws of nature are formulated, but also that, quite apart from their primary significance for the field in which they arose, they have a secondary anagogic value in other fields, in which they become symbols, often of great efficacy. Only the lower alchemists sought to evolve gold from baser metals and this quest we now know was always and everywhere really subordinate to the effort to evolve the summum bonum in human life. So the modern sciences that deal with life and death, health and disease, are really directed far more than they know, even in those researches upon the lower forms of life and most abnormal processes, by the deeper, determining motivation to know better and to influence more the conditions of human life. Thus a truer and larger self-knowledge for man is, in this sense, their ultimate goal.

In view of this, what psychologist can for a moment doubt that the old problem which F. W. H. Myers called the most insistent that ever haunted the mind of man has contributed very much to stimulate interest in Weismann’s doctrine of the immortality of the germ plasm and for a wide lay public has given a zest and interest in phenomena that can hardly be observed at all save through a microscope and by an expert. If we had an analysis of Weismann’s own consciousness from his first conception of this idea to its full development we should doubtless find the same factor. True, we search his writings in vain for any intimation that he recognized any such influence, but I think there can be no doubt that had he been a psychologist interested in the sources of his own motivations and had he left us an autobiography as intimate as that of Spencer, Wundt, or even Darwin, we should have seen that he realized that he was only giving a new answer to the oldest of all culture problems. Of course, no psychoanalyst or geneticist would claim that Weismann was seeking an elixir vitæ or a new fountain of youth for himself or for others, but it would be equally extreme, on the other hand, to deny that in the very use of the concept and term immortal, as he applied them to germ plasm and protozoa, he was propounding a new if partial surrogate answer to the problem of a larger life for man. Indeed, we might go further and suggest that in his extreme pronouncements against the inheritance of acquired qualities he gave way to the same basal disposition or diathesis that made theologians so exiguous in formulating conceptions of the inviolability of divine decrees.