336 LUTHER BURBANK 



But be the explanation what it may, the fact 

 remains that very few fruits in a state of nature 

 are white; and no one needs to be told that fruits 

 of the many tribes of blackberries, with the single 

 exception of the one under present discussion, are 

 of a color fully to justify the name they bear. 

 Yet the experiment in breeding just recorded 

 proves that, at least under the conditions of arti- 

 ficial selection, a race of berries may be devel- 

 oped which, though having the flavor and con- 

 tour of the blackberry, is as far as possible from 

 black in color. 



The fact that this race of white berries was 

 developed in the third generation from parents 

 one of which is a jet black fruit and the other a 

 fruit of a brownish tint, seems at first glance to 

 give challenge to the laws of heredity. 



ATAVISM AND UNIT CHARACTERS 



Even though we should assume that a remote 

 ancestor of our newly developed white black- 

 berry might have been a pure albino, the case 

 still seems mysterious. Cases of reversion to the 

 type of a remote ancestor have been observed 

 from time to time by all breeders of animals and 

 by students of human heredity, and it has been 

 customary to explain such cases of reversion, or 

 at least to label them with the word "atavism." 



