526 INHERITANCE OF MENTAL TRAITS 



The Importance of Eugenics. — There is no evi- 

 dence that the decreased birth rate in the superior 

 classes is to any great extent due to biological causes. It 

 is probably due entirely to the voluntary acts of individ- 

 uals in the postponement of marriage and the prevention 

 of conception. There is the possibility, therefore, that 

 the situation may be saved by education in eugenics. 

 The difficulty is that although it is relatively easy to 

 teach people the significance of the issues involved, it 

 is very hard to persuade them to care enough about the 

 future of civilization to make any sacrifices in its behalf. 



It is evident, at any rate, that man faces few, 

 if any, problems of greater importance for his future 

 welfare than those relating to the control of heredity. 

 By the strict application of eugenic principles it would 

 be possible to reduce greatly the number of defectives, 

 to increase the production of genius, and to improve 

 the average level of morality and intelligence. 



The Effect of Undesirable Immigration. — The 

 mental tests given to nearly two million of our soldiers 

 during the recent war disclosed large differences in the 

 intellectual ability of various racial groups. Evidence 

 to the same effect is also available from numerous ex- 

 perimental studies. The following conclusions seem 

 warranted. 



1. Probably not more than 10 or 15 per cent of Ameri- 

 can Negroes equal or exceed in intelligence the average 

 White. The intelligence of the average Negro is vastly 

 inferior to that of the average white, and the mulatto 

 occupies a position about mid-way between. 



2. The intelligence of the average American Indian is 

 appreciably but not greatly superior to that of the aver- 

 age Negro. Our Mexican population (Indian hybrids 

 for the most part) which has recently increased with 

 groat rapidity, barely surpasses the Negro in average 

 enrlowment. 



3. The immigrants who have been coming to us from 



