560 EVOLUTION, GENETICS, AND EUGENICS 



death. We would not push the conclusion too far, but we can not 

 doubt that this investigation shows the folly of ignoring the environ- 

 ment — shows that the best inherited constitution must have a fair 

 chance. And what has here been found for a physical character, 

 would probably hold good in even greater degree for a mental charac- 

 ter. All that man inherits is the capacity to develop along a certain 

 line under the influence of proper stimuU, food and exercise. The 

 object of eugenics is to see that the inherent capacity is there. Given 

 that, the educational system is next needed to furnish the stimuli. 

 The consistent eugenist is therefore an ardent euthenist. He not only 

 works for a better human stock but, because he does not want to see 

 his efforts wasted, he always works to provide the best possible envi- 

 ronment for this better stock. 



In so far, then, as euthenics is actually providing man with more 

 favorable surroundings — not with ostensibly more favorable sur- 

 roundings which, in reality, are unfavorable — there can be no antago- 

 nism between it and eugenics. Eugenics is, in fact, a prerequisite of 

 euthenics, for it is only the capable and altruistic man who can con- 

 tribute to social progress; and such a man can only be produced 

 through eugenics. 



Eugenic fatalism, a blind faith in the omnipotence of heredity 

 regardless of the surroundings in which it is placed, has been shown 

 by the study of long-Uved families to be unjustified. It was found 

 that even those who inherited exceptional longevity usually did not 

 Uve as long as their inheritance gave them the right to expect. If they 

 had had more euthenics, they should have Uved longer. 



But this illustration certainly gives no ground for a belief that 

 euthenics is sufficient to prolong one's life beyond the inherited limit. 

 A study of these long-lived famiUes from another point of view will 

 reveal that heredity is the primary factor and that good environment, 

 euthenics, is the secondary one. 



For this purpose we augment the 100 families of the preceding 

 section by the addition of 240 more families like them, and we examine 

 each family history to find how many of the children died before com- 

 pleting the fourth year of life. The data are summarized in the table 

 on page 488. 



The addition of the new families (which were not subjected to any 

 different selection than the first 100) has brought down the child 

 mortaUty rate. For the first 100, it was found to be 7.5 per cent. If 

 in the above table the number of child deaths, 1 19, be divided by the 



