582 HUMAN BIOLOGY 



Galton and of school children and college students by Terman 

 and by Gowen have shown that Galton's conclusion is 

 well founded that "nature prevails enormously over nur- 

 ture when the differences of nuture do not exceed what is 

 commonly to be found among persons of the same rank of 

 society and in the same country." 



WHAT ARE THE PROBABILITIES OF RACE IMPROVEMENT? 



The Hmitations of eugenics as a means of race improve- 

 ment lie in the field of practical appHcation rather than of 

 genetical principles. Some of these practical difficulties in 

 the path of eugenic progress can be overcome with an 

 aroused social conscience, and with increased knowledge of 

 human inheritance and development the time may soon 

 come when all highly civilized nations will prevent by 

 segregation or sterilization the propagation of the worst 

 elements in society. This is already being done in many 

 states and nations by the segregation of the feebleminded, 

 insane and criminals in asylums and prisons. It is doubtful 

 whether it will ever be possible to segregate or sterilize 

 normal persons who are known to come of tainted stock and 

 hence may carry inherited defects as recessive factors. By 

 means of simpler and more effective means of sterilization 

 and especially by methods of preventing conception such 

 persons may choose to be childless, and in a stationary 

 population, which we may except within a few centuries, 

 public sentiment may be a great aid in restricting the 

 reproduction of the unfit. Indeed sentiment and custom are 

 much more potent in such matters than are legal enactments. 

 Already the practice of voluntary birth control is wide- 

 spread and is rapidly solving the population problem, and 

 it is not improbable that it will also help to solve the problem 

 of the propagation of hereditary defects, for people with 

 even a modicum of intelligence would prefer to have no 

 children rather than to have defective ones. 



More important and still more difficult of accomplish- 

 ment than such measures of negative eugenics are the 

 perpetuation and increase of the best elements in human 

 society, or the promotion of positive eugenics. As civilized 

 society is at present organized the most intelleuctal, progres- 



