42 Mutability and Individual Variation. 



subjects it to a stringent criticism nor does he devote 

 a separate section to it. Furthermore in the treatment 

 of single instances this thesis is taken for granted with- 

 out further proof. One sees this most clearly in the 

 discussion of the apple :^ It is known, he says, that all our 

 kinds of apples spring from the wild Pyrus Mains and 

 that from this over a thousand different forms have been 

 developed. This gives one the impression that cultiva- 

 tion produced these numerous forms. But as a matter 

 of fact the apple in the wild condition is a polymorphous 

 species rich in subspecies and the w^ell differentiated types 

 which are now cultivated already exist among the wild 

 forms. The transformation of the wild crab apples into 

 juicy and finely flavored fruits is all that has been brought 

 about by cultivation. 



It is an absolutely unproved assumption that individ- 

 ual variation extends its range by selection and increases 

 "to an enormous extent^ This is the weak point in 

 Wallace's selection theory. 



I admit that with this assumption it would be very 

 easy and simple to account for the phenomena of adap- 

 tation, and that this forms a very strong argument for 

 it. And if it were only a matter of this explanation little 

 purpose would be served by raising objections to it. 



But it is, as a matter of fact, fallacious. Selection 

 certainly leads to enormous practical results, but that is 

 a very different thing from enormous biological changes. 

 The fact that a man can increase the yield per acre by 

 one-half, has no significance from the point of view of 

 the origin of species. In the third chapter I shall seek 

 to prove this by the help of facts. 



it is not necessary to follow Wallace's argument 



* Loc. cit., p. 87. 



