380 EVOLUTION AND GENETICS 



size of their families in proportion to their means. All too often 

 families are limited in spite of their means, and in this we must 

 agree with Shull's statement: "If, in some cases, selfishness leads 

 to a desire to avoid children, and if selfishness is inherited, as 

 it presumably is to a large extent, such people are probably 

 doing the race a service by permitting their lines to be extin- 

 guished." 



It seems very probable that most persons do not give such 

 matters serious attention, and that sheer indifference is a contrib- 

 uting factor in their failure to reproduce. There are so many 

 attractive activities in the modern world to occupy the individual's 

 time that mere conflict of interests may result in the limitation 

 of family without any sense of race consciousness or economic 

 pressure entering the matter. Such a tendency must probably 

 be construed as a degree of selfishness; if so it is a very common 

 fault. The same indifference undoubtedly contributes to the 

 fecundity of the lower classes, who merely obey the powerful 

 instinct of reproduction without thought of the social and economic 

 consequences. 



Immigration and the Birth Rate. Immigration is a national 

 problem for more reasons than one which cannot be considered 

 here, but it has had an important effect in the maintenance of 

 desirable elements in the population of the United States which 

 bears definitely on the problems of eugenics. 



Such men as Carnegie and Steinmetz are fine evidences of our 

 indebtedness to foreign countries even within recent jTars for men 

 of exceptional ability. Our native American population must 

 acknowledge its foreign ancestry within a few generations of 

 ancestors, but even since the establishment of a fairly definite 

 American stock we have drawn constantly upon the European 

 nations. Opportunity has been the keynote of immigration; in 

 America lay opportunity which the Old World could not furnish 

 and many valuable men have taken advantage of it. 



It is difficult to say what might have been the accomplishment 

 of such men if they had stayed in their own countries. One can 

 hardly imagine them contented with anything less than a leading 

 role in their chosen fields, yet the class hmitations of Europe are 

 undeniably more stringent than those of America and can scarcely 

 have afforded ample opportunity for the development of their 

 genius. Given the opportunity of America, where achievement 



