LUTHER BURBANK 



selection, a race of berries may be developed 

 which, though having the flavor and contour 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 assume that a remote ancestor 

 of our newly developed white blackberry was a 

 pure albino, the case still seems mysterious. Sim- 

 ilar 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." 



If this word be taken to imply that all traits 

 and tendencies of an ancestral strain are carried 

 forward from generation to generation by heredity, 

 even though unable to make themselves manifest 

 for many generations, and that then, through some 

 unexplained combination of tendencies, the sub- 

 merged trait is enabled to come to the surface and 

 make itself manifest, the explanation must be 

 admitted to have a certain measure of tangibility. 



[54] 



