Modification of Germinal Constitution of Organisms 197 



These experiments in synthesis represent what might 

 happen in a state of nature when species which can hybridize 

 migrate from one place to another and intercross. No 

 one realizes better than I the complexity of experiments 

 of this kind, the difficulties involved in the analysis of the 

 results, and the caution that should be exercised in making 

 statements from them. It seems certain from these experi- 

 ments, as far as they have been carried out, and they are 

 by no means complete, that we may definitely conclude 

 that when like materials are combined under different 

 natural environments, differences in the products, depending 

 upon the conditions under which the combination takes 

 place, result. It is certain that the type which came out of 

 the culture in the Balsas Valley was quite different from 

 that which resulted from the cultures at Orizaba, and these 

 are different from the dominant type which arose at Tucson. 



One point of very considerable interest is the behavior of 

 these dominant types in exactly the way in which DeVries' 

 Oenothera Lamarckiana behaves, giving in each generation, 

 a greater or less number of rather divergent individuals, 

 which, when inbred, are found to be stable germinal varia- 

 tions. 



Bateson in 1902 suggested that the mutations observed 

 by DeVries in Oenothera Lamarckiana are in reality due to 

 some sort of hybridization behavior. I am of the opinion 

 that Bateson's suspicion is probably justified, at least in 

 some instances. I have no experience with plants, and 

 especially none with O. Lamarckiana, but my experience 

 with these synthetic experiments has suggested that the 

 type of behavior which DeVries has discovered, and 

 upon which he has built an all-inclusive theory of evo- 

 lution, is in reality nothing more than the reappearance 



