Mimetic Resemblances in Animals and Plants. 

 By Eev. Pkof. George Henslow, M.A. 



Insufficiency of Natural Selection. 



Mimetic resemblances in animals, either to others or to objects in 

 their natural environments, are mostly regarded as protective ; and 

 this feature of protection has been assumed to be their rationale, or, 

 in a sense, the " cause " of their existence. Darwinians assume that 

 the animals which resemble their neighbours, by possessing a similar 

 coloration and by adopting similar habits, are the result of the survival 

 of the fittest, all others insufficiently resembling the protectors, i.e. 

 all " unfavourable variations," having been killed off by natural 

 selection. 



Thus, Professor E. B. Poulton has lately published a paper on 

 "Natural Selection, the Cause of Mimetic Eesemblances and Common 

 Warning Colours " ; 1 but in no part of it does he explain how natural 

 selection can be " a cause." If he use the term metaphorically, it is 

 misleading, for the other hypotheses mentioned in the paper do profess 

 to supply actual physical causes, viz. " the direct effect " of the 

 external conditions of life, or an " internal developmental cause." 

 Natural selection is not " a cause " in any physical sense whatever. 

 It only means, according to Darwin, "the preservation of favourable 

 individual differences and variations, and the destruction of those 

 which are injurious. This (he says) I have called Natural Selection, 

 or the Survival of the Fittest." 2 On several occasions Professor 

 Poulton discards all other hypotheses, and says, " Under the theory 

 of natural selection the facts at once receive an explanation." Un- 

 doubtedly they may ; if only its supposed powers were true and not 

 imaginary. Natural Selection seems not unlike the wand of the fairy, 

 which could evolve a coach and six out of a pumpkin and mice. 

 But, in fact, all that it can tell us is, that some beings live and others 

 die. It can neither account for the physical cause of a useful variation 

 in one organism, nor say why another organism dies. It only, so to 

 say, registers the fact. 



1 ./"urn. /.in. Sue. (Zool.) xxvi. 1S98, p. 558. 

 - "Origin of Species," p. 63. 



I 2 I 



