PLAN AND PURPOSE IN NATURE. 215 



animal kingdom of a structure or an instinct, which should 

 be shown for certain to be of exclusive use to any other 

 plant or animal than the one presenting it, and committed 

 himself to the bold statement that he would surrender his 

 whole theory of natural selection upon the production of a 

 single true instance of this occurrence. He was so assured 

 of the truth of his theory that he could not accept for a 

 moment the belief that natural selection could ever have 

 permitted (sic) an adaptive structure or instinct to occur 

 in one species for the exclusive benefit of another. Others 

 have followed in the same strain, and the gage of battle 

 is supposed to be lying where Darwin threw it forty years 

 ago, no champion being prepared to take it up. 



33 Romanes* even carried this argument and challenge fur- 

 ther, thinking that Darwin did not make a sufficient weight 

 of evidence from this point. He triumphantly supposed it to 

 be unanswered and unanswerable, and his remarks upon it 

 are highly interesting. The only two instances in all the 

 millions of vegetable and animal structures of adaptation 

 which he would consider, and these he firmly set aside, are 

 the sweet secretion of aphides which ants cultivate for their 

 own advantage, a case produced by Darwin himself and dis- 

 allowed, and the formation of vegetable galls which are of 

 value to the nurture and protection to the larvee of insects. 

 This case Romanes also set aside as explicable b}^ natural 

 means ; or, failing this, as the result of accident. 



34 Milnes Marshall in his able lectures on the Darwinian theory 

 also disposes of this argument in a very summary fashion. 

 He says,t " that there is evidence that any animals or plants 

 are specially designed to satisfy the wants or to delight the 

 senses of man is most absolutely denied; and could such cases 

 be proved, they would be fatal to the whole theory. In nature 

 those characters alone are preserved which are advantageous 

 to the species." But this old and fair argument on behalf of 

 the evolutionist, and against the teleologist, is not to be dis- 

 posed of in this summary style. We are not shut up to a few 

 trifles such as the "• milk " of aphides, or vegetable galls. It 

 is possible to state an argument with apparent candour, and, 

 with a desire for information which would do credit to Rosa 

 Dartle. However, if the argument be put forward at all we 

 cannot be forced into a corner, dazzled with the light of a 



* Darwin and after Darwin, vol. i, pp. 286 to 295. 

 t Lectures on the Darwinian Theory, 1894, p. 171. 



