National Geographic : 1919 Jun
WHO SHALL INHERIT LONG LIFE? On the Existence of a Natural Process at Work Among Human Beings Tending to Improve the Vigor and Vitality of Succeeding Generations BY DR. ALEXANDER GRAHAM BELL AUTHOR, IN THE NATIONAL GEOGRAPHIC MAGAZINE, OF "PRIZES FOR THE INVENTOR," "DISCOVERY AND INVENTION," "OUR HETEROGENEOUS SYSTEM OF WEIGHTS AND MEASURES," "AERIAL LOCOMO TION," AND "A FEW THOUGHTS CONCERNING EUGENICS" MOST people die before reaching middle life, and comparatively few live to be old. This has always been so from the very earliest times; and, in spite of modern sanitation and the advance of medical sci ence, remains true today. Only a small proportion of each generation survives the traditional Biblical age of threescore years and ten. Under these circumstances is it not re markable that so many people should have parents who lived to be old? Seventy is by no means an unusual age for a parent. Examine the history of the people you know and you will find that very few of them had parents who died before sev enty, while a considerable proportion had parents who lived to be eighty or even much older. An examination of several hundred cases, noted in the Genealogy of the Hyde family 1 , shows that 18.7 per cent of these persons lived to be seventy or older; but 81.7 per cent had fathers or mothers who lived beyond seventy. About 13 per cent lived to seventy-five; but 65 per cent, or nearly two-thirds of the whole, had fathers or mothers who lived beyond sev enty-five. The contrast is still more marked when we consider persons who lived to extreme old age. Only 8.7 per cent lived to be eighty or older; and yet 48.1 per cent, nearly one-half of the whole, had fathers or mothers who lived to be eighty or older. 1 Genealogy of the Hyde Family, by Reuben H. Walworth, LL. D ., 1864; a work relating to the descendants of William Hyde, one of the early' settlers of Norwich, Conn., who died in 1681. These are the results of an investiga tion of 1,594 cases in which the ages at death of the persons and of their fathers and mothers were all known. 2 Such results seem to point to the gen eral conclusion that "avery large propor tion of each generation has sprung from a very small proportion of the preceding generation,namely, from the people who lived to be old. Another inference is that the long-lived people left more descendants behind them in proportion to their numbers than the others, and therefore, on the average, had larger families. Of course, many widowers may have married again when they were well ad vanced in years and have had families by each marriage, but this explanation does not apply to women. MOTHERS' AGES AN INDEX TO THE SIZE OF THEIR FAMILIES We cannot, for example, suppose that mothers who died at fifty would have had more children had they lived to be sixty or eighty or a hundred; and yet investi gation shows that the mothers who lived to extreme old age actually had, on the average, larger families than those who died earlier in life. From the Hyde statistics we find that mothers who died before forty had, on the average, only 3.4 children apiece; and this is intelligible because many of the mothers passed away long before the con clusion of the reproductive period,. and 2 See "The Duration of Life and Conditions Associated with Longevity, A Study of the Hyde Genealogy," by Alexander Graham Bell; published by the Genealogical Record Office, 16o0 35th Street, Washington, D. C. $ .oo.