386 STUDIES, SCIENTIFIC AND SOCIAL chap. 



remain in a more or less unstable or rudimentary con- 

 dition ; and when we further consider that many genera 

 and families extend far back into geological time and 

 must have originated in the midst of a physical and 

 biological environment very different from that which now 

 prevails, we shall dimly understand how complex are the 

 forces and processes which have led to the assemblage of 

 characters now presented by each organism, and how 

 difficult it must be to determine positively that any one 

 of these characters is not, nor ever has heen, useful to its 

 possessor. Yet this is what is done by those writers who 

 maintain, as did the late Mr. Romanes, that the majority 

 of specific characters are not and never have been useful, 

 but have arisen through definite variation under the 

 influence of definite causes, and, when neither useful nor 

 hurtful, persist and constitute the main external differ- 

 ences which we observe between species and species. 

 This theory, which, although to some extent held by 

 Darwin himself, I consider to be wholly erroneous, we will 

 now proceed to discuss. 



It may be well first to dispose of a point, made much 

 of by Mr. Romanes, that I do not urge utility as a charac- 

 teristic either of varieties or of genera and higher groups, 

 and that it is therefore illogical to claim it for species. 

 But this is a misapprehension, since I do claim that 

 when varieties are constant, are hereditary, and occupy a 

 definite area, and are therefore what Darwin termed 

 " incipient species," the characteristics which distinguish 

 them from the parent species are, to some extent, adaptive 

 and useful, and will become fully so when the variety 

 becomes a fully differentiated species. And as to genera 

 and families, it is obvious that every one of their dis- 

 tinguishing characters was once a specific character, since 

 genera are merely groups of species, all of which were 

 derived from one parent species, and which have become 

 more or less isolated by the extinction of intermediate 

 forms. Families are, in the same way, derived from a 

 single genus and ultimately from a single species, and the 

 same reasoning applies to them. The reason why my 

 argument on this question has been limited to species is, 



