Vernon y m a n Kellogg 



R. BURBANK has so far not for- 

 mulated any new or additional 

 laws of species-change, nor do his 

 observations and results justify any 

 such formulation, and we may 

 rest in the belief that he has no new fundamental 

 laws to reveal. He has indeed the right to formu- 

 late, if he cares to, some valuable and significant 

 special conclusions touching certain already recog- 

 nized evolution factors, in particular, the influence 

 on variability of the two long-known variation- 

 producing factors of hybridization and modifica- 

 tion of environment. His reliance on the marked 

 increase in variability to be got after a crossing in 

 the second and third generations over that obvious 

 in the first will come as a surprise to most men 

 first getting acquainted with his work. He has 

 got more starts for his new things from these gen- 

 erations than in any other way. He is wholly clear 

 and convinced in his own mind as to the inheri- 

 tance of acquired characters ; ' acquired characters 



85 



