Human lifespan

“ Now it takes the human animal twenty years at least to grow to maturity; therefore the human animal really should live five times twenty years, which makes a round hundred or a CENTURY; and I firmly believe it is intended for him to live that long, if he only acted in accordance with the laws of life and health. And, dear uncle, you seem always to have acted so, and therefore I think you may safely calculate upon living out your century and then dying the gentle death of mere old age. ”

“ Why should seventy or eighty years remain as the usual limit of human life? Why should its natural duration under perfectly healthy surrounding conditions not be at least 100 years, with an occasional extension of some ten or fifteen years more? ”

“ Variations from different causes are essentially distinct from a regular and unretrograde increase. The average duration of human life will to a certain degree vary from healthy or unhealthy climates, from wholesome or unwholesome food, from virtuous or vicious manners, and other causes, but it may be fairly doubted whether there is really the smallest perceptible advance in the natural duration of human life since first we have had any authentic history of man. ”

“ My own life work, such as it is, as a genetic psychologist was devoted for years to the study of infancy and childhood, then to the phenomena of youth, later to adulthood and the stage of sex maturity. To complete a long-cherished program I have now finally tried, aided by the first-hand knowledge that advancing years have brought, to understand better the two last and closing stages of human life. ”

“ They trick our natural mechanisms. That kind of thing is commonplace in medicine today. But our research is poised for the next level, to answer the question of how long we can actually live. So here's the argument. There's no reason the human life span has to be what it is. In some unhealthy nations the average citizen doesn't even reach sixty. ”

“ Add these considerations, and its value as a guide becomes immediately apparent; a new light is poured upon a hundred problems of the greatest delicacy and difficulty. Not the least interesting of these is the gradual extension of human longevity—an extension, however, which cannot be effected till many [Pg 382] many generations as yet unborn have come and gone. ”

“ Recognizing the fact that the essential cells in our241 body are inherently capable under proper conditions of living indefinitely, the problem that confronts us is whether environment or heredity has most to do in determining the actual length of life. Pearl163 concludes that the death rate of the earliest period of life is selective, eliminating the weak and leaving the strong, and that inheritance is “one of the strongest elements, if not indeed the dominating factor, in determining the duration of life of human beings.” ”

“ Two things are very obvious,—the uncertainty as to the hour of death in individuals, but the regularity and constancy of the circumstances which influence the duration of human life in the aggregate. It is a matter of certainty that the average life of all persons born in this country extends to about forty-five years. ”

“ With regard to the duration of human life, there does not appear to have existed, from the earliest ages of the world, to the present moment, the smallest permanent symptom, or indication of increasing prolongation. ”

“ But he does regard that period as more nearly the normal length of human life than the commonly accepted limit of sixty-five or seventy, and as possibly attainable through the advance of medical science. Though he comes of a short-lived family and all his brothers died at an age much younger than he has now attained, his health is unusually good for a man of seventy, and he is as hard-working and enterprising as ever. It is not the mere prolongation of life for which he is working, but the prolongation of the period of serviceable and enjoyable life. ”

“ He has suggested further that if the normal specific longevity were attained by human beings, old and not degenerate individuals would lose the instinct for life and acquire an instinct for death, and that as they had fulfilled the normal cycle of life, they would accept death with the same relieved acquiescence that they now accept sleep. ”

“ The outline of this law is, indeed, clearly defined, and can be traced in every table—a high rate of mortality in the first year of life, decreasing until the minimum is reached somewhere near the age of puberty, then rising very gradually, until with old age a very rapid increase takes place. But, while these general traits are well established, the details are subject to continual deviations.
We must assume that there is a fundamental law of life accompanying the organization of the human being, but that it is
English Life Table No. ”

“ And if the cycle of human life followed an ideal course, he concluded men and women after living a healthy and useful life extending over at least a century, with their usefulness and satisfaction in life at maximum during the latter portion of that period, would then give themselves up calmly and gracefully to the arms of death, as to the arms of a friend laying them down to earned and wished-for rest. Old age would have no terrors, and death no victory. ”

“ With respect to the latter circumstance, indeed, there are so very many causes contributing to shorten considerably the length of human life, that we have completely lost every criterion by which to estimate its original duration; and it would be no slight problem for a profound physiological science to discover and explain from a deeper investigation of the internal constitution of the earth, or of astronomical influences, which are often susceptible of very minute applications the primary cause of human longevity. ”

“ Even for the short planetary life-span of the average human, the logic of this position seems inescapable, whether it applies to the next hour, day, year, or century. In terms of our children and grandchildren it is even more impressive. ”

“ By this means, the human race is undoubtedly being weakened, human life shortened, and diseases multiplied. Compare the average age of human beings of the present day, less than forty years, with the longevity of the early members of the race, who lived more than as many score of years. Some mighty deteriorating influence has been at work; and we hazard nothing in the assertion that the marriage of diseased persons and kindred violations of the laws of human hygiene have been not unimportant factors in producing this most appalling diminution in the length of human life. ”

“ Cradock, 'we may say that all ages are dangerous to all people, in this dangerous life we live.'
'Reflecting how, at the best, human life on this minute and perishing planet is a mere episode, and as brief as a dream....' ”

“ The years from about eight to twelve constitute a unique period of human life. ”

“ Bernard Shaw108 thinks mankind is headed straight for the City of Destruction and can be saved not by eugenics or by a new and better education, as H. G. Wells opines, but by prolonging human life to circa139 three hundred years. If the length of life were reduced to one-half or one-quarter of what it now is we may assume that our culture and institutions would decline because children could not direct them. ”

“ The more healthy and perfect her organization, and the better the balance of all her organs, the sounder and the more perfect will be the development of her offspring. The health and life of the child demand it.
This theory of human increase derives strong evidence from an analogous law in the animal and vegetable kingdoms. It is well known that great improvements have been made within the present century in domestic animals, and this, too, by the application of physiological laws. ”

“ So long as human nature remains the same, this splendor and pomp of processions, these lighted torches and ornamented churches, this triumphant music and glad holiday of religion will attract more than your plain conventicles, your ugly meeting-houses, and your compromise with the bass-viol. ”

“ It becomes evident, then, that as we ascend in the scale of Life we rise also in the scale of longevity. The lowest organisms are, as a rule, shortlived, and the rate of mortality diminishes more or less regularly as we ascend in the animal scale. ”

“ As every one knows, every creature, man included, lives about as long after the maximum power to propagate as his offspring requires to become mature, so that the prolongation of the period of immaturity means the prolongation of old age. Our foremost duty is to transmit the sacred torch of life undimmed, to give the maximal momentum and right direction to the nature and nurture of offspring and to bring rising generations to their full maturity—that is the highest criterion of an ever rising nation, including civilization itself. ”

“ Consider also after this, that there is no stability of our body: childhood passes to boyhood, and boyhood to full growth; full growth bows to age, and age is ended by death. Verily our age stands on no stability, but so much as the body grows so greatly are its days diminished. Everywhere in our life are faintness and weariness, and decay of the body, and yet every one desires that he may live long. ”

“ But that which interested me most in reckoning up their divisions of time was the ascertainment of the average duration of life amongst them. I found on minute inquiry that this very considerably exceeded the term allotted to us on the upper earth. What seventy years are to us, one hundred years are to them. Nor is this the only advantage they have over us in longevity, for as few among us attain to the age of seventy, so, on the contrary, few among them die before the age of one hundred; and they enjoy a general degree of health and vigour which makes life itself a blessing even to the last. ”

“ These more marked nodes in the unity of man’s individual existence are: (1) childhood, (2) adolescence from puberty to full nubility, (3) middle life or the prime, when we are at the apex of our aggregate of powers, ranging from twenty-five or thirty to forty or forty-five and comprising thus the fifteen or twenty years now commonly called our best, (4) senescence, which begins in the early forties, or before in woman, and (5) senectitude, the post-climacteric or old age proper. ”

“ Each movement is so quiet, yet so decided, so living, so human, that the radiant creature seems a Musidora of the water, and you almost blush with a sense of guilt, in gazing on that peerless privacy. ”

“ Before we advert to the nature of our adaptations for this period of life, we must draw a distinction between age and "premature old age." The former is the decline of nature, which must always take place, whilst the latter is the result of disease or improper habits. ”

“ If in my hour of agony and shame I could implore the help of any human being, I would come to you—dear, honest, brave girl!—before all others, to fling myself at your feet, and kiss your hands, and beseech you to pity me and save me from myself, to hold my hot head on your gentle bosom, and your soothing hand on my fierce heart. ”

“ A social aggregate which has chosen the fatal path of organic evolution must succumb to the same law of organic development to which all organisms are subject, namely greater and greater organization, increase of structure, greater differentiation, decrease of critical, personal, consciousness, loss of individual liberty, increased activity of the subconscious forces, falling into a state of somnambulism which can only be redeemed by revolution or by death. ”

“ So, too, we speak of middle age and think vaguely of it as half way between birth and death or between adolescence and senescence. If we think of life as a binomial curve rising from a base line at birth and sinking into it at death, midway is the highest point with the longest ordinate; and as the crest of a wave has its spindrift, so life at this point often foams, or at least shows emulsive tendencies. We come in sight of the descent while the ascent behind is still visible. ”

“ An early bloom is too apt to presage an early decay; and though our mortuary statistics, thanks to the advance of medical and sanitary science, do undoubtedly show that [Pg 79] the average duration of life is becoming more and more extended, and that the Golden Age, in this respect, is before us rather than in the past ”

“ The real question, then, is, How does the longevity of this select class of thirty-seven-year-old men compare with that of more ordinary individuals? The answer is given by the expectation of life at thirty-seven years, which is twenty-nine years, making the average age at death sixty-six years. And this is precisely the age at death of these sixty great men; showing that, as a class (for these sixty may be considered a fair sample) great men are not distinguished by longevity from other men. ”

“ The average specific longevity, on the other hand, depends on a multitude of extrinsic conditions operating on the intrinsic constitution; these extrinsic conditions are given by the environment of the species as it affects the young and the adults, enemies, diseases, abundance of food, climatic conditions and so forth. ”

“ As a matter of fact the average length of life is steadily increasing, because science is teaching men how to live so as to conserve health and youth. Formerly men and women grew old very much earlier than they do now, and they died much younger. ”

“ Survival, therefore, must not be conceived as completed at a bound, but as slowly perfected by a gradual and continuous lengthening of the average span of life. It must be shown, however, that such a survival would constitute a superiority, not only for the individual, but for the species. ”