Page:Popular Science Monthly Volume 71.djvu/410

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POPULAR SCIENCE MONTHLY

the results. With these results it appears to me that Darwinism is clearly and definitely established for man.

It is not so many years ago since a distinguished statesman, speaking within the walls of this university, asserted that, "No man has ever seen natural selection at work." At that time all the criticism

PSM V71 D410 Graph related to the study of longevity.png

Fig 5.

possible seemed, "Every man who has lived through a hard winter, every man who has examined a mortality table, every man who has studied the history of nations, has probably seen natural selection at work." And thirteen years later I should add: The time has now come for statesmen to inquire whether natural selection is doing its work efficiently; that it applies to man no longer admits of question. Can it possibly be that agencies under the control of the legislator are suspending that Platonic purification of the state which in olden time natural selection worked almost automatically?

Table VIII.
Natural Selection in Man. Percentages of Deaths due to Selective Death Rate
Deduced from Age at Death of Kindred
From Parental Heredity Data From Fraternal Heredity Data
Value Selected % Non-selected Value Selected % Non-selected
.3 67.5 32.5 .4 84.1 15.9
.4 58.4 41.6 .45 79.3 20.7
.45 55.1 44.9 .5 75.2 24.8
Thus between 55 and 75 per cent, of deaths in the case of man are selective.