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|- |colspan=4 style="text-align:center;font-variant:small-caps;font-size:110%;padding-bottom:0.5em;"|Table VII. |- |colspan=4 style="text-align:center;font-variant:small-caps;font-size:110%;padding-bottom:0.5em;"|Inheritance of Ability. Male and Male |- |colspan=4 style="text-align:center;font-style:italic;font-size:105%;padding-bottom:0.5em;"|Paternal Inheritance |-style="border-top:4px double black;text-align:center;border-bottom:1px solid black;" |width=180 style="border-right:1px solid black;padding-top:0.5em; padding-bottom:0.5em;"|Method |width=120 style="border-right:1px solid black;padding-top:0.5em; padding-bottom:0.5em;"|Authority |width=120 style="border-right:1px solid black;padding-top:0.5em; padding-bottom:0.5em;"|Ages |width=120 style="padding-top:0.5em; padding-bottom:0.5em;"|Intensity |- |style="text-align:left;padding-top:0.5em;border-right:1px solid black;"|Oxford class lists |style="text-align:left;padding-left:0.5em;padding-top:0.5em;border-right:1px solid black;"|Schuster |style="text-align:left;padding-left:0.5em;padding-top:0.5em;border-right:1px solid black;"|Adults |style="padding-top:0.5em;padding-right:4em;"|.49 |- |style="text-align:left;padding-bottom:0.5em;border-right:1px solid black;"|Family records |style="text-align:left;padding-left:0.5em;padding-bottom:0.5em;border-right:1px solid black;"|Pearson |style="text-align:left;padding-left:0.5em;padding-bottom:0.5em;border-right:1px solid black;"|Adults |style="padding-left:0.5em;padding-bottom:0.5em;padding-right:4em;"|.58 |- |colspan=4 style="border-top:1px solid black;border-bottom:1px solid black;text-align:center;font-style:italic;font-size:105%;padding-top:0.5em; padding-bottom:0.5em;"|Fraternal Inheritance |- |style="text-align:left;padding-top:0.5em;border-right:1px solid black;"|Oxford class lists |style="text-align:left;padding-left:0.5em;padding-top:0.5em;border-right:1px solid black;"|Schuster |style="text-align:left;padding-left:0.5em;padding-top:0.5em;border-right:1px solid black;"|Adults |style="padding-top:0.5em;padding-right:4em;"|.56 |- |style="text-align:left;border-right:1px solid black;"|Family records |style="text-align:left;padding-left:0.5em;border-right:1px solid black;"|Pearson |style="text-align:left;padding-left:0.5em;border-right:1px solid black;"|Adults |style="padding-right:4em;"|.54 |- |style="text-align:left;border-right:1px solid black;"|School class lists |style="text-align:left;padding-left:0.5em;border-right:1px solid black;"|Schuster |style="text-align:left;padding-left:0.5em;border-right:1px solid black;"|Boys |style="padding-right:4em;"|.56 |- |style="text-align:left;text-align:left;padding-bottom:0.5em;border-right:1px solid black;"|School observations |style="text-align:left;padding-left:0.5em;padding-bottom:0.5em;border-right:1px solid black;"|Pearson |style="text-align:left;padding-left:0.5em;padding-bottom:0.5em;border-right:1px solid black;"|Boy and boy |style="padding-bottom:0.5em;padding-right:4em;"|.52 |- |}

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

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