LUTHER BURBANK 



feasible, by inbreeding, to develop a race of 

 crinkled-leaved heuchera. It would have been im- 

 possible to develop and fix this race so rapidly had 

 pains been taken to cross the plant showing the 

 peculiarity with a normal plant, instead of cross- 

 ing it with a cousin showing the same peculiarity. 



In quite the same way such a human abnormal- 

 ity as a tendency to deafness or a malady of the 

 eyes or feeblemindedness or susceptibility to 

 tuberculosis may be accentuated through cousin 

 marriages and thus brought out in the progeny, 

 where, had mating occurred with a normal strain, 

 the tendency might have been indefinitely sub- 

 merged or even eliminated. 



MENDELISM AND HUMAN MALADIES 



It has been shown that the phenomena of 

 Mendelian inheritance apply to a number of ab- 

 normal conditions to which human beings are 

 subject. It seems fairly established, for example, 

 that normality of mind and feeblemindedness 

 constitute a Mendelian pair of unit characters or 

 unit groups in which normality is dominant and 

 feeblemindedness recessive. 



It follows that the offspring of a normal indi- 

 vidual and a feebleminded one may be all normal 

 in mind; and if these individuals mate exclusively 

 with normal individuals, the character for feeble- 

 mindedness may be permanently submerged. 



[242] 



