RACE SUICIDE OR A NATURAL LAW? 29 



we shall find as we proceed ample evidence that intel- 

 lectual activity is inimical to fertility, and if this result 

 is so marked among the completely sterile it should be 

 capable of reducing the average fertility of the rest. 

 Why is it necessary to appeal to natural infertility in one 

 case and not in the other ? 



What are the implications if, as Dr. Whetham admits, 

 the sterility of the childless marriages is due to natural 

 causes ? It is impossible to assume that the environ- 

 ment has picked out a certain number of couples and 

 annihilated their fertility, while leaving the fertility of 

 the remainder unaffected. When wild animals are con- 

 fined it is found that the very fertile types are rendered 

 only moderately fertile ; that the moderately fertile 

 types are rendered only slightly fertile ; and that the 

 slightly fertile types, such as parrots, are rendered com- 

 pletely sterile. So, then, with the wives of Cambridge 

 professors and others. We should expect that conditions 

 which render completely sterile those whose natural 

 fertility is very slight would render the moderately fertile 

 individuals only slightly fertile, and the very fertile 

 individuals only moderately fertile. The low average 

 fertility, therefore, is the logical consequence of condi- 

 tions which render so large a proportion completely 

 sterile. 



Those classes the members of which combine a com- 

 fortable income with a considerable degree of intellectual 

 activity have invariably a very small average family, 

 and a very large proportion of completely childless couples. 

 Thus the average number of children among the English 

 intellectuals is about 1*5, and the proportion of childless 

 marriages among any selected body of them will usually 

 work out at from 25 to 33 per cent. Taking a list of 

 twenty-eight of the leading members of the Eugenics 



