II THE ORIGIN OF SPECIES 75 



which was, even in the least degree, infertile with 

 the first. Mr. Darwin is perfectly aware of this 

 weak point, and brings forward a multitude of 

 ingenious and important arguments to diminish 

 the force of the objection. We admit the value of 

 these arguments to their fullest extent ; nay, we 

 will go so far as to express our belief that experi- 

 ments, conducted by a skilful physiologist, would very 

 probably obtain the desired production of mutually 

 more or less infertile breeds from a common stock, 

 in a comparatively few years ; but still, as the case 

 stands at present, this " little rift within the lute " 

 is not to be disguised nor overlooked. 



In the remainder of Mr. Darwin's argument our 

 own private ingenuity has not hitherto enabled us 

 to pick holes of any great importance ; and judging 

 by what we hear and read, other adventurers in 

 the same field do not seem to have been much 

 more fortunate. It has been urged, for instance, 

 that in his chapters on the struggle for existence 

 and on natural selection, Mr. Darwin does not so 

 much prove that natural selection does occur, as 

 that it must occur ; but, in fact, no other sort of 

 demonstration is attainable. A race does not 

 attract our attention in Nature until it has, in all 

 probability, existed for a considerable time, and 

 then it is too late to inquire into the conditions of 

 its origin. Again, it is said that there is no real 

 analogy between the selection which takes place 

 under domestication, by human influence, and any 



