370 ME. G. J. EOMAlSnES ON PHYSIOLOGICAL SELECTION. 



in the way hitherto supposed by evolutionists * ; but that 

 the primary distinction is in most cases, as I have just ex- 

 pressed it, a local variation in the organism, which has to do 

 only with the reproductive system. Why, then, should we 

 suppose that it differs from a local variation taking place in any 

 other part of the organism ? "Why should we suppose that, 

 unlike all other such variations, it cannot be independent, but must 

 be superinduced as a secondary result of variations taking place 

 elsewhere ? It appears to me that the chief reason why evolu- 

 tionists suppose this, is because the particular variation in 

 question happens to have as its result the origination of species ; 

 and that, being already committed to a belief in other agencies 

 as the cause of such origination, in consistency they are obliged 

 to regard this particular kind of local variation as not indepen- 

 dent, but superinduced as a secondary result of these other 

 agencies operating on other parts of the organism. In short, it 

 appears to me that by persistently regarding the primary specific 

 distinction as a derivative and incidental result of the secondary, 

 evolutionists are putting the cart before the horse ; and the only 

 reason they can show for choosing this arrangement is that they 

 already assume the origin of species to have been due to other 

 causes, and in particular to natural selection. But once let them 

 clearly perceive that natural selection is concerned with the 

 origin of species only in so far as it is concerned with the origin 

 of adaptive structures, or only in so far as it is concerned with 

 some among the many secondary distinctions — once let naturalists 

 be perfectly clear upon this point, and they will perceive that 

 the primary specific distinction takes its place beside all other 

 variations as a variation of a local character, which may, indeed, 

 at times be due to the indirect influence of natural selection, use, 

 disuse, and so forth ; but which may also be due to any of the 

 other numberless and hidden causes that are concerned with 

 variation in general. 



Thus, I repeat, what we require in a theory of the origin of 

 species is a theory to explain the primary and most constant 

 distinction between species, or the distinction in virtue of which 

 they exist as species. This distinction, as we have now so re- 

 peatedly seen, is one that belongs exclusively to the reproductive 

 system ; and it always consists in comparative sterility towards 



* I do not think that Mr. Darwin himself entertained this supposition, and 

 therefore I have not his authority against me. 



