Page:Popular Science Monthly Volume 71.djvu/409

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Table VII.
Inheritance of Ability. Male and Male
Paternal Inheritance
Method Authority Ages Intensity
Oxford class lists Schuster Adults .49
Family records Pearson Adults .58
Fraternal Inheritance
Oxford class lists Schuster Adults .56
Family records Pearson Adults .54
School class lists Schuster Boys .56
School observations Pearson Boy and boy .52
Mean paternal value, .54. Mean fraternal value, .54.

the healthiest, leave most offspring.[1] One link still remains unproven: Are these variations subject to selection? Is the death rate in man a function of his constitution? Or does man fall in his youth or prime or dotage by the purely random bolt of death? The possibility of

PSM V71 D409 Graph related to the study of longevity.png

Fig. 4.

solving this last problem occurred to me when studying the inheritance of longevity. If longevity depended only on the physical constitution, we might expect it to be inherited at the same' rate as other physical characters. I found it to be inherited always at a lesser rate. The difference could only be accounted for by the partly random character of death's aim. This was the key to measuring the proportion of the selective and non-selective death rates in man. Table VIII. gives you

  1. The data are from the records of the Society of Friends, and show with little doubt an unrestricted birth rate.