342 LUTHER BURBANK 



Stated otherwise this means that so-called 

 "spontaneous" variation, which Darwin found so 

 mysterious, is really due, or for the most part 

 due, to the bringing together of diverse ancestral 

 strains through cross-fertilization and their new 

 responses to present environment. 



It is varieties thus developed that furnish 

 material for the operation of national selection, 

 through which as Darwin taught us new 

 species have been evolved in the past and are still 

 being evolved. 



I think I had more than half fathomed this 

 mighty secret before I had made extensive ex- 

 periments in plant hybridization. But in any 

 event I had not gone far with my experiments in 

 plant development before I found evidence 

 piling up on every side to reassure me that what 

 I had heard was no illusory voice but the voice 

 of nature herself. 



Doubtless no single tribe of plants served me 

 better in this connection, or were more obviously 

 the medium through which nature's great secret 

 was revealed and corroborated, than the tribe of 

 plums. And in the forefront of the company, 

 in this connection, must be named the twelve little 

 seedlings from Japan. 



If I had entertained any doubt as to the cor- 

 rectness of these premonitions, the results 



