58 



MAN THE ANIMAL 



tlon, and one who dies at seventy or over as long lived. These 

 ranges in general agree fairly with common-sense opinion and 

 usage. 



Figure 6 shows the percentages of the fathers and mothers re- 

 spectively that had (a) both of then parents long-lived (shown 

 by the solid black portion of each bar) \ (b) one parent long- 

 lived and the other mediocre or short-lived (shown by the cross- 



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0£A'£j9y^ LL Y 



/WAD 



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P£OPL£ 

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 /.or/e-Liyao 



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A^£-/r/^£^ P^/?£A/r 



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Fig. 6. The percentage distributions, relative to the nature of the parental matings 



producing them, of the fathers and of the mothers of (a) an extremely longevous 



group (nonagenarians and centenarians), and (b) a defined 



sample of people generally 



hatched portion of each bar) ; and (c) neither of their parents 

 long-lived (shown by the white portion of each bar). 



The picture presented is precise and striking. The non- 

 agenarians and centenarians were produced by parents who were 

 themselves bred out of wholly longevous parentage in more 

 than half of all the cases observed — a markedly higher propor- 

 tion than that shown by the parents of the general population 

 sample. At the other end of the genetic scale the opposite is true. 

 Fewer than half as many proportionally of the nonagenarians 



