THE BREEDING OF MEN 



vitally important there may be reversion to a re- 

 mote ancestor. 



The really vital question is whether, in prac- 

 tice, there is any definite guide as to this mat- 

 ter of the inheritance from remote ancestors of 

 traits that are not manifest in the immediate 

 ancestors. 



Fortunately this question may now be answered 

 in the affirmative. The new knowledge that makes 

 this possible was gained primarily through the 

 study of inheritance in plants. 



Thus Mr. Burbank early discovered that when 

 he hybridized two plants having different qual- 

 ities the progeny of the first filial generation were 

 relatively uniform in character, but that their 

 progeny showed a very strong tendency to varia- 

 tion, some of them reverting toward one parent 

 and others toward the other, and still others show- 

 ing a new combination of the traits of the parents. 



It was by following up the clews thus given 

 that Mr. Burbank was able to make many of his 

 most important plant developments. 



As an illustration, Mr. Burbank crossed a par- 

 tially thornless bramble that had been discovered 

 in the eastern United States with the ordinary 

 thorny blackberry, and produced a race of hy- 

 brids all of which bore thorns. But in the next 

 generation a certain number of the progeny were 

 thornless ; and some of them combined with thorn- 

 lessness the good qualities of fruit-bearing of 

 their thorny grandparent. 



On the same principle, Mr. Burbank produced 

 [255] 



