What may be maintained, and properly so, is that muta- 

 tion constitutes one way, at least, by which new forms 

 of organisms may arise on the world's surface. New 

 forms, in the sense of the new combinations of old charac- 

 ters which come into being by reason of stable, non-re- 

 verting hybrids, are known to have originated, but such 

 new forms imply of course the pre-existence of varied 

 types, and do not have to do with the Question of the 

 origin of new characters. 



It is not in the order of things that a new theory of such 

 import as the Mutation Theory should not find oppo- 

 nents. These I think may, in the main, be grouped in 

 three classes. First, the critics who doubt the evidence, 



I 



who can be answered by referring them to the printed 

 records, and recommending a repetition, as careful as the 

 original work, of the experiments which have led to the 

 new point of view. Second, those who quibble concern- 

 ing terms, and this type I think constitutes the majority, 

 who will likely suffer the fate that is usually meted out to 

 quibblers, that of being ignored. Lastly, those opponents 

 who, while they may not doubt the accuracy of the work, 

 doubt the conclusions on philosophical grounds. These 

 are the critics whom the advocate of the De Vries Theory 

 must welcome and who will arrest his sober attention, for 

 they will stimulate him to accumulate more and more evi- 

 dence to support his position. Even were I able to analyze 

 adequately the controversial side of the question for you, 

 it is obvious that time scarcely allows, and I will, in conse- 

 quence, state frankly that the account which I have pre- 

 sented is from the standpoint of an advocate of what the 

 Mutation Theory teaches, and add that I am not aware 

 that any experimental work has controverted it. Let me 

 say, however, and here I wish to speak for myself alone, 

 that I cannot see it makes great odds whether fifty years 

 hence or five years hence we accept the Mutation Theory 



28 



