416 HEREDITY AND ENVIRONMENT 



point of view the person who is voted the "best 

 all round man in the class" is nearer the 

 eugenical ideal than the prize scholar. 



No man can trace his lineage back through 

 many generations without realizing that it in- 

 cludes many hereditary lines differing greatly 

 in value. The significance of sexual reproduc- 

 tion lies in this very fact that it brings about 

 the commingling of distinct lines and thereby 

 makes every individual different from every 

 other one. The entire history of past evolu- 

 tion testifies to the value of this process, al- 

 though it causes the gardener, the breeder, the 

 eugenicist serious trouble. But the gardener 

 can propagate his choice fruits by budding and 

 grafting, the breeder can for a time preserve 

 his choice stock by close inbreeding, but the 

 eugenicist cannot shut out the influence of for- 

 eign blood, and it is well that he cannot for 

 if he could do so the progress of the race 

 would probably come to an end. 



In the human species the only absolute bar- 

 rier to the intermingling of races is geographi- 

 cal isolation. Every human race is fertile with 

 every other one, and though races and nations 



