LUTHER BURBANK 



thousands of children are born into the world 

 foredoomed to disease or to defective mentality 

 by the mismating of their parents. 



In the older conception, heredity was fatalistic. 

 So long as it was believed that all the character- 

 istics of a parent are transmitted to all his chil- 

 dren, it seemed inevitable that the sins of the 

 parents must be visited upon the children, in strict 

 accordance with the biblical mandate. But the 

 new knowledge of Mendelian heredity makes it 

 clear that the hereditary factors in the germ- 

 plasm of an individual may be potent or impotent 

 in their tangible influence on the next generation, 

 according to the combinations that are made with 

 the hereditary factors of the other parent. 



We have seen, for example, that factors for 

 mental deficiency or for susceptibility to consump- 

 tion, even though present in the germ-plasm of 

 an individual, may be utterly unable to make 

 themselves tangibly manifest if that individual 

 mates with one in whose germ-plasm the factors 

 for normal mentality only and for resistance to 

 consumption are present. 



Thus the mandate that seemed to condemn the 

 offspring may in many cases be rendered nuga- 

 tory by the right selection of marriage partners. 



Here, then, is a specific instance in which a 

 definite knowledge of the laws of heredity might 

 serve to determine whether the offspring of an 

 individual should be normal or defective; where, 

 in a word, the principles of eugenics might be 

 practically applied with benefit to a fraternity of 



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