CONTROL OF HEREDITY: EUGENICS 437 



most as dangerous for fertility as is captivity 

 for wild animals. It is evident that if we had 

 fewer luxuries we could have, and could afford 

 to have, more children. 



But animals in captivity may gradually be- 

 come adapted to their new conditions so as to 

 become fertile, and there is evidence that a 

 slow adaptation through several generations 

 to conditions of high civilization is possible. 

 Some royal families of Europe go back six or 

 eight hundred years, and in general if a family 

 survives the new conditions of affluence and 

 luxury for more than three generations it may 

 become more or less adapted to the new 

 conditions. 



What Bernard Shaw regards as the greatest 

 discovery of the nineteenth century, viz., the 

 means of artificially limiting the size of fami- 

 lies, may prove to be the greatest menace to the 

 human race. If it were applied only to those 

 who should not have children or to those who 

 should for various reasons have only a few chil- 

 dren it would be a blessing to mankind. But 

 applied to those who could and should have 

 many children it is no gift of the gods. No 



