THE 



AMERICAN NATURALIST 



Vol. L. September, 1916 



THE STATUS OF THE MUTATION THEORY, 

 WITH KSPKOIAL RUFERHXCK To 

 OENOTHERA 1 



DR. HARLEY HARRIS BARTLETT 

 The more or less controversial literature of the muta- 

 tion theory is so scattered and involved that few except 

 specialists have been able to follow it with any degree of 

 satisfaction. A recent book by Gates, "The Mutation 

 Factor in Evolution, with Particular Reference to (Eno- 

 thera," will help the general biologist to an understanding 

 of the situation, but even in the short time since it went 

 to press there have been developments of such signifi- 

 cance that I am glad of this chance to review the subject. 

 The crux of the whole controversy is this: Are the dis- 



