114 Social Environment 



acted as a magnet drawing to itself the most 

 capable strains of the surrounding population, 

 from whose superior capacity has developed in 

 later generations the relatively high percentage 

 of noted men? 



There is considerable evidence that such is 

 not the case. To begin with, the great cities of 

 the United States are of very recent growth ;^ 

 the frontier of one generation becomes the 

 teeming urban region of one or two genera- 

 tions later, peopled by the descendants of the 

 pioneers, and by later immigrants. But the 

 selection hypothesis requires a considerable 

 period through which selection may do its 

 work effectively; for in the first place it must 

 be remembered that the able young man going 

 to the city and there winning fame is credited 

 not to the city but to the environment of his 

 birth; and in the second place biological prin- 

 ciples show that the changing of the innate 

 characteristics through selection is only accom- 

 plished laboriously and slowly.^ Further, the 

 selection hypothesis is greatly weakened by the 

 fact previously shown that it is not so much 

 the stock of the great city that is fertile in 



^ Abstract of Thirteenth Census, p. 93. 

 2_Castle, W. E.. et al.. Heredity and Eugenics. The 

 University of Chicago Press, Chicago, 1912. 



