CHAPTER XV 



A CRITIC OF XATUKAL 8ELECTI0X ANSWERED 



In Natural Science of July, 1894, the Rev. George Henslow 

 makes some statements with regard to variation and Natu- 

 ral Selection which call for critical remark, especially as 

 they have been treated with great detail in a popular work 

 by the same writer, and are thus likely to spread erroneous 

 views as to Darwin's discoveries, as well as to the general 

 theory of Evolution through variation and the survival of 

 the fittest. He says that, though cultivated plants vary 

 indefinitely, and therefore require selection to produce 

 definite modifications, this is not the case in Nature — 

 " Variation in Nature is always in strict adaptation to the 

 direct action of the environment ; in other words, natural 

 variation is always definite." This statement seems to 

 me so extraordinary, and so opposed to well-known facts, 

 that I can only impute it to the use of the terms " vary " 

 and " variation " in two very distinct senses ; first, as 

 meaning those individual variations which occur abund- 

 antly both in nature and under cultivation ; and, 

 secondly, as meaning those particular variations which 

 alone survive under nature and produce either a " variety " 

 or ultimately, a " species." In this latter sense, of course, 

 " natural variation" is definite; but so, in the same sense, 

 are the variations of cultivated plants. From unstable 

 and indefinite '" variations " man and nature alike produce 

 definite " varieties." As one out of the innumerable ex- 

 amples of indefinite variation which might be named, are 



VOL. I. X 



