338 MB. G-. J. ROMAliTES ON PHTSIOLOGICAL SELECTION. 



fore, in now adopting an attitude of criticism towards certain 

 portions of Mr. Darwin's work, I cannot feel that I am turning 

 traitor to the cause of Darwinism. On the contrary, I hope thus 

 to remove certain difficulties in the way of Darwinian teaching ; 

 and I well know that Mr. Darwin himself would have been the 

 first to welcome my attempt at suggesting another factor in the 

 formation of species, which, although quite independent of 

 natural selection, is in no way opposed to natural selection, and 

 may therefore be regarded as a factor supplementary to natural 

 selection. 



DlEPICULTIES AGAINST NATURAL SELECTION AS A ThEORT OP 



THE Origin of Species. 



The cardinal difficulties in the way of natural selection, con- 

 sidered as a theory of the origin of species, are three in number : — 



1st. The difference between natural species and domesticated 

 varieties in respect of fertility. 



Mr. Darwin himself allows that this difference cannot be ex- 

 plained by natural selection ; and indeed proves very clearly, as 

 well as very candidly, that it must be due to causes hitherto unde- 

 tected. As we shall presently find, he treats this difficulty at 

 greater length and with more elaboration than any other ; but, as 

 we shall also find, entirely fails to overcome it. Now, seeing of 

 how much importance to any theory on the origin of species is 

 the great and general fact of sterility between species, I need not 

 wait to show how heavily we must here discount the theory of 

 natural selection, considered as a theory to explain the transmu- 

 tation of species. 



2nd. Another fact of almost equal generality is that the 

 features, even other than sterility inter se, which serve to dis- 

 tinguish allied species, are frequently, if not usually, of a kind 

 with which natural selection can have had nothing whatever to do ; 

 for distinctions of specific value frequently have reference to 

 structures which are without any utilitarian significance. It is 

 not until we advance to the more important distinctions between 

 genera, families, and orders that we begin to find, on any large or 

 general scale, unmistakeable evidence of utilitarian meaning. 



This difficulty, as I have MS evidence to show, was first per- 

 ceived by Mr. Darwin himself ; it was afterwards presented in a 

 formidable shape by the Grerman palseontologist Bronn, and sub- 

 sequently by Broca, Nageli, and sundry lesser writers as regards 



