CONTROL OF HEREDITY: EUGENICS 435 



disappearing and in a few centuries at most 

 will have given place to more fertile races of 

 mankind. Everybody knows that the old 

 New England families are dying out and that 

 their places are being taken by recent immi- 

 grants. The few exceptions are merely eddies 

 in the current that is bearing them to doom. 

 In Massachusetts the birth rate of the foreign 

 born is twice that of the native population while 

 the death rate is about the same. The same 

 is true of the older families in many parts of 

 the world. 



Professor Cattell has recently made a sta- 

 tistical study of the families of 917 Ameri- 

 can men of science and he finds that the 

 average size of family of the parents of these 

 men was 4.66 children, whereas the average 

 size of family of these men is 2.22 children. 

 In one generation the fertility of these lines 

 has been reduced by more than half. The 

 causes of this decline are chiefly voluntary 

 being assigned to health, expense and other 

 causes. 



But the causes of sterility are not only so- 

 cial and voluntary ones, which could be 



