350 Darwin, and after Darwin. 



among the thousands of vertebrated species, should no 

 one of their eyes be constructed on the ideal pattern 

 that was devised for the cuttle-fish ? Of course it may 

 be answered that perhaps there was some hidden reason 

 why the design should never have allowed an adapta- 

 tion which it had devised for one division of organic 

 nature to appear in another even in cases where the 

 new design necessitated the closest possible resem- 

 blance in everything else, save in the matter of anatomi- 

 cal homology. Undoubtedly such may have been the 

 case or rather such must have been the case if the 

 theory of special design is true. But where the ques- 

 tion is as to the truth of this theory, I think there can 

 be no doubt that its rival gains an enormous advan- 

 tage by being able to explain why the facts are such 

 as they are, instead of being obliged to take refuge 

 in hypothetical possibilities of a confessedly unsub- 

 stantiated and apparently unsubstantial kind. 



Therefore, as far as this objection to the theory of 

 natural selection is concerned or the allegation that 

 homologous structures occur in different divisions of 

 organic nature not only does it fall to the ground, 

 but positively becomes itself converted into one of the 

 strongest arguments in favour of the theory. As 

 soon as the allegation is found to be baseless, the 

 very fact that it cannot be brought to bear upon any 

 one of all the millions of adaptive structures in 

 organic nature becomes a fact of vast significance on 

 the opposite side. 



The next difficulty to which I shall allude is that 

 of explaining by the theory of natural selection the 

 preservation of the first beginnings of structures which 



