LUTHER BURBANK 



being made tangible in some of the progeny 

 under favorable conditions. 



The laws of Mendelian inheritance show us 

 that the factors of heredity may be so redis- 

 tributed that individuals of the same parentage, 

 and hence precisely the same heredity, broadly 

 speaking, are radically different in their innate 

 hereditary tendencies as regards some minor but 

 perhaps not inconsequential qualities. 



The new knowledge does not controvert the 

 old rule that "like produces like," but it gives us 

 new insight into the interpretation of that rule. 

 In its practical bearing on the interpretation of 

 heredity as applied to human beings, the new 

 knowledge takes precedence in importance over 

 all that has hitherto been known about heredity. 



Until the Mendelian interpretation was avail- 

 able, no one could pretend to fathom the mysteries 

 of atavism, much less to predict as to the prob- 

 able recurrence of submerged ancestral qualities 

 in any given generation. 



But the Mendelian formula serves as a work- 

 ing hypothesis that enables us in many cases to 

 predict with a fair degree of certainty what will 

 be the result of the union of individuals of known 

 heredity. 



Thanks to this hypothesis, however, the laws of 

 heredity in their application to the human organ- 

 ism now take on a definiteness that they hitherto 

 have lacked. 



[286] 



