292 Heredity and Environment 



from savagery to civilization. And yet he has not consciously set 

 before himself an evolutionary goal to be attained by intelligent 

 attention to principles of good breeding. 



II. CAN HUMAN EVOLUTION BE CONTROLLED? 



Almost all that man, now is he has come to be without conscious 

 human guidance. If evolution has progressed from the amoeba to 

 man without human interference, if the great progress from ape- 

 like men to the most highly civilized races has taken place without 

 conscious human control, the question may well be asked, Is it 

 possible to improve on the natural method of evolution? It may 

 not be possible to improve on the method of evolution and yet 

 by intelligent action it may be possible to facilitate that method. 

 Man cannot change a single law of nature but he can put himself 

 into such relations to natural laws that he can profit by them. 



i. Selective Breeding the only Method of Improving the Race. 

 It is surely not possible to 'improve on nature's principle of elim- 

 inating the worst lines from reproduction. This* has been the chief 

 factor in the establishment of races of domesticated animals and 

 cultivated plants, though as we have seen it has probably had 

 nothing to do with the origin of mutations. The history of such 

 races shows that evolution may be guided to human advantage 

 by intelligent elimination and selection, and probably any heredi- 

 tary improvement of the human race must be accomplished by 

 this means, though of course such elimination and selection can 

 apply only to the function of reproduction. The method of evo- 

 lution by the elimination of persons, the destruction of the weak 

 and cowardly and antisocial, which was the method practiced in 

 ancient Sparta, is repugnant to the moral sense of enlightened 

 men and cannot be allowed to act as in the past; but the worst 

 types of mankind may be prevented from propagating, and the 

 best types may be encouraged to increase and multiply. This is 

 apparently the only way in which we may hope to improve per- 

 manently the human breed. 



