LUTHER BURBANK 



of the primrose that explains in any precise 

 way the relation of the change to the particular 

 differences, let us say, between the soil of the 

 original home of the primrose and the soil of 

 Holland. Moreover in numberless other instances 

 plants have been transplanted from one region to 

 another without showing any such pronounced 

 tendency to develop new races. 



It was recognition of the difTiculties thus 

 presented, undoubtedly, that led Professor de 

 Vries to devise the rather visionary hypothesis of 

 periods of mutation with which his theory was 

 cumbered. 



But it is a well recognized law of logic 

 that one should never seek remote and obscure 

 explanations of observed phenomena unless all 

 explanations of a more tangible character have- 

 been proved untenable. And it has seemed to 

 me from the outset that in the case of the evening 

 primrose a very much more plausible explanation 

 is at hand than the one devised by the originator 

 of the mutation theory. 



In a word, the varied tribes of evening primrose 

 which Professor de Vries developed in his gardens 

 at Amsterdam were overwhelmingly suggestive of 

 various and sundry new forms of hybrid plants 

 that I mj'^self have developed year after year in 

 my experimental gardens at Santa Rosa. 



[96] 



