PREFATORY NOTE 31 



in species making he very definitely 

 questions. In the application of a knowl- 

 edge of heredity to the art to which it 

 gives rise in the plant world his suprem- 

 acy is unchallenged. 



I quote again from Burbank: "A 

 knowledge of Mendelism is recognized 

 by me as only the A B C to the broader 

 knowledge of heredity necessary for 

 success in animal and plant improve- 

 ment, and all variations and all muta- 

 tions of every nature are responses to 

 environment which, by repetition and 

 combination, are slowly but surely fixed 

 in heredity and at last made tangible, 

 most often through the crossing of 

 varieties, species, or genera, either by 

 nature or that part of nature called 



man.' 



Among other things Burbank has 

 shown that while "sex is not a necessary 

 attribute of all living things," it is "a 



