Senescence, the Last Half of Life

by G. Stanley Hall

So vital and rapidly growing are these bacteria that they would soon, under favorable conditions, outbulk the entire body. But while their numbers are kept down by lack of nutriment and other conditions, nature provides no adequate antidote to their activity. This was found by Woolman and was called glycobacterium, or the sugar-maker. It was found first in the dog, and it can be cultivated in the laboratory and introduced into the body. It transforms starch into sugar without affecting the albuminoids and it is not, like sugar, absorbed before it reaches the large intestine. Thus it is not sugar that is the antidote but the lactic acid of its product and this is found in nature in the bacillus of sour milk, a common article of diet among Bulgarians, who seem to be the longest-lived people in Europe. The results of experiments with this product, first upon rats and other animals, Metchnikoff thought remarkably rejuvenating; and as all know, many substances containing lactic acid were for a long time in great favor, although expectations of its effectiveness have by no means been fulfilled. The death of Metchnikoff himself, too, at the age of seventy-one, who had long and diligently used his own panacea, did not help the confidence of his disciples, for we can never forget the old slogan, “Physician, heal thyself.”

In Sanger’s returns to his questionnaire,[170] as well as to my own, one often finds people who use some form of this preparation and with what they deem good results and Metchnikoff’s volumes show such a unique combination of humanistic and scientific interests that they have had wide popularity.

The problems, however, with which he deals are so extremely complicated that his work may really be said to have propounded more problems than he solved. He believed he had found and even named specific phagocytes attacking most, but not all, of the main tissues and organs of the body. Cohorts of them encamp about cells, very slowly absorbing their substance and depleting their energies—some attacking muscles; others, heart and arteries, etc.; others consuming the pigment cells of the hair which, however, as Pohl showed, continues to grow as rapidly in old age as in youth, as do the finger nails; others making the bones porous and brittle by removing the lime from them and transferring some of it to the walls of the arteries; some even specializing to attack brain and nerve cells. We must fight fire with fire, and to do this we must not only introduce the sugar-making bacteria but provide them with food in situ in order that they may do their great work of purifying the cradle or breeding ground of noxious bacilli. Some of his disciples are still enthusiastic enough to believe that just as we purified the Panama Zone; as vaccination has almost annihilated smallpox, which once caused about one-tenth of all deaths; as Behring’s antitoxin has greatly abated the scourge of diphtheria; as Wright’s vaccine has lessened death from typhoid; as Ehrlich’s salvarsan treatment has done so much for syphilis, and as he and Wassermann hope may be done for cancer—so we may yet find and learn how to use a specific that, although it will not realize the dreams of those who once sought an elixir of life, will nevertheless contribute to its perhaps indefinitely great prolongation. This Metchnikoff does not hesitate to call “the most important problem of humanity.” His ideal is what he calls orthobiosis, which is “the development of human life so that it passes through a long period of old age in active and vigorous health leading to the final period in which there shall be present a sense of satiety of life and a wish for death.” Mere prolongation of life in the sense of Herbert Spencer is not in itself desirable. When the wish for death comes, he thinks that under certain circumstances suicide would be quite justifiable. Old age, he believes, will not only be greatly prolonged but will become optimistic. Pessimism he finds commonest among young men, while many avowed pessimists have become optimistic in their old age. Young men will not so precipitately attempt to displace the old, as he finds to be too much the case now, but the latter will attain greater power and influence.

The constitution man has inherited from his anthropoid ancestors is far from fitting his present environment. The greatest disharmony of all is the morbid nature and brevity of the period of old age. Man does not round out his prescribed cycle and develop in its final stage an instinct for and love of death, as he should. He is expelled from the school of life at all stages of its curriculum but always before the final or senior year, until the fact that there was such a final grade has been almost forgotten. It was because man felt himself prematurely cut off that he developed all dreams of resurrection and of another life. Had he completed his life here he would never have wanted or dreamed of another. Had the involution that begins usually in the fifth decade or earlier gone on normally, it would have made each stage of the recessional no whit less delightful than those of the processional of youth till, having withdrawn more and more from life and being in the end quite satiated with it, the individual would have rejoiced to see the limitations that separate him from ultimate reality fall away until he merges, body and soul, into the cosmos from which he came. Only the simplest organisms are immortal and as we ascend the scale and develop a more complex soma, the more impossible does any kind of immortality become. Metchnikoff seeks nothing of this sort but would simply increase the number of years and enrich them in the last phase of our existence so that, instead of being the pitiful remnant it now is and instead of having to console itself so pathetically by the puerile and unsubstantial figments that religions and philosophies have given us, man would enter upon the full heritage that nature intended for him. Thus the highest goal of all endeavor is to overcome the present degeneration of senescence, to cultivate physiological old age; and when this ideal is realized, more and more of the complex and intricate affairs of social, industrial, political, and other forms of life will be left to the old men, for these things require not only technical training but, perhaps even more, the wide view, insight, and common sense for which experience with life is the best school.

Metchnikoff was able to discover only two ideal cases of old people in whom his “instinct for death” was well developed. But he believes that as gerontology advances this instinct will not be the exception but the rule and that the very nature of old age as we know it will be radically transformed. At present we know little more of it than the prepubescent child knows of sex or the embryo of its mother’s milk. When the instinct for death is well developed, we shall long for it as we do for sleep when we are fatigued, for old age is The Great Fatigue. Many instincts of the young are reversed and pass over into their ambivalent opposite at a later stage of life; and so the love of life will, in the end, be transformed into the love of death. Both animal and human parents devote their lives to the service of their offspring during the period in which this is necessary; but when the latter are mature, we often find a reversal of this instinct. Perhaps the intense sensitiveness of ova and spermotozoa displayed in the phenomena of chemotaxis and in the marvelous power of regeneration of lost parts among many lower forms of metazoa, and the many phenomena that led Haeckel to call the soul of cells immortal, are lost later as higher, conscious psychic powers develop; and if so, this shows the marvelous transformability of the primitive impulses that dominate simpler forms of life.

Thus Metchnikoff is a humanist as well as a scientist. He sets down faithfully what he saw through the microscope, but not content with that ventures to indulge his speculative instincts and tell the world what he thinks his discoveries mean for the practical conduct of life and of mind—and that, too, in more or less untechnical terms that make his ideas accessible to intelligent laymen. For him, as for Plato, “philosophy is the art of preparing for death.” He even urged that “the instinct for death seems to lie in some potential form deep in the constitution of man,” and it was this he sought to develop. The only basis for all modern forms of belief in immortality roots in a platonic reminiscence of the processes of the deathless germ plasm, and from this the old soma and the, no whit less, old psyche have departed as far as possible. Psychic life, too, has its proximate beginnings in the intense vitality of germ plasm and cells and from these rudiments the adult human consciousness has so far developed that our conscious psyche knows no more of it than it does of the migrations or depredations of the phagocytes within the body. Man is the most pathetic of beings because of the two tides whose ebb and flow constitute his life—evolution and de- or in-volution, anabasis and catabasis. He has failed, on account of the action of the intestinal fauna within him, to achieve any adequate sense of appreciation, still less enjoyment of the refluent currents. Man is thus deprived of the nascent period in which this wooing of death is due to arise and does not reach his true end or final goal. Dreamy illusions about it have always haunted his soul as unsubstantial surrogates. When man now in the making is finished, what we at present call old age will be a sort of superhumanity, a new and higher story, and its completion will spontaneously bring with it new and deeper insights; and he will approach and finally enter Nirvana with the same zest and buoyancy with which he now takes possession of life.

Crude and amateurish as often is Metchnikoff’s philosophy, his courage, candor, and the strength of his convictions are commendable, and the faith he adds to his knowledge is full of hope. From his ideal thinker, Schopenhauer, he caught the flavor of the Vedanta and Upanishads but he did not see how these very ideals also underlay the mystic hermetic philosophy of the medieval alchemists and their royal art, as modern symbolists like Hitchcock and Silberer interpret them; and to this I shall revert later. If he overestimated the value of his panacea and ventured into fields of other experts in which he was ignorant and where he was often mistaken, he has at least made a very valuable addition to the yet all too meager literature on senectitude, which all thoughtful and intelligent aging people can read not only with profit but with pleasure, if only they have escaped from the narrow limits of orthodox Philistia. To have really edified this now ever growing section of all civilized countries is a real culture service. His work is uniquely inspired by a spirit psychologically very akin to that which impelled Buddha when he set out on his mission of finding The Way, stimulated to do so by the sight of an aging man and a putrefying corpse.[171]

Charles Sedgwick Minot, an embryologist, (d. 1914, a.e. 62) devoted most of his maturer years to a study of the phenomena of growth, keeping and daily weighing many young animals, especially guinea pigs, and he has left us a good compendium of his life work.[172] Stated in the most general terms, he held that old age and death were progressive phenomena that began in the individual with life itself, that the best method of measuring vitality was the rate of growth, and that this constantly diminishes and finally ceases. As soon as, for example, guinea pigs recover from the disturbances caused by their birth, which are great and last two or three days because they are born at a very advanced stage of development, they add from 5 per cent to 6 per cent to their weight during a single day. But this percentage diminishes, so that by the end of the first month they add only 2 per cent; at ninety days, only 1 per cent; and the diminution continues, rapidly at first and then more slowly. Calculating the time to make successive additions of 10 per cent, there are twenty-five of these additions; and not until we reach the seventeenth addition do we find nine days or more necessary. The twenty-second addition takes four days, the later ones being somewhat irregular. The first ten per cent increment often comes in two days.

Chicks, too, are born highly developed, and so lose during the first day. Then the daily percentage of increase is greater than in the guinea pig. From the sixth to the tenth day inclusive the average is nearly but not quite 9 per cent; at the end of the third month, only 2 per cent. Rabbits are born very immature and, being less developed, grow more rapidly. The average for males of the first five days of growth is over 17 per cent. The rabbit thirty days old has about the same daily percentage of increase as the new-born guinea pig. The human child takes 180 days to double its weight; a horse, 60; a cow, 47; goat, 19; pig, 18; sheep, 10; cat, 9½; dog, 8; rabbit, 6–7, these rates depending, in part, on the quality of the mother’s milk.

In embryos the rate of growth is still more rapid. The increase in the guinea pig in the first five days is 3,520 per cent, or an average of 704 per cent daily. From the fifteenth to the twentieth day it is 1,058 per cent, or an average of 212 per cent per day. Thus the rate of growth during the foetal period is far more rapid and it is more so in the earlier than in the later stages of embryonic development. The farther back we go, the more rapid is this rate. Thus his curves show a very steep decline in the rate of growth, even in its earlier stages, and this decline continues, although at an ever decreasing rate, to the end. Thus from this point of view the younger creatures are, the more rapidly they are dying. The weight of a fertilized germ he estimates at 0.6 milligram (and he tells us that 50,000 of these could go by mail for a two-cent stamp). Thus the human embryo at birth has increased 5,000,000 per cent of its initial weight. Old age is merely the later result of changes that have gone on at a diminishing rate ever since the ovum from which we originated was fertilized.