OBJECTIONS TO EVOLUTION 171 



benefit to the creature presenting it; for the creature 

 would thus be able to seek the one and shun the 

 other, according to the requirements of its life. And 

 being thus useful from the very moment of its incep- 

 tion, it would afterwards be gradually improved as 

 variations of more and more utility presented them- 

 selves, until not only would finer and finer degrees of 

 difference between light and shade become percept- 

 ible, but even the outlines of solid bodies would begin 

 to be appreciated. And so on, stage by stage, till 

 from an ordinary nerve, ending in the skin, is evolved 

 the eye of an eagle. 



"Moreover, in this particular instance there is very 

 good reason to suppose that the modification of the 

 cutaneous nerves in question began by a progressive 

 increase in their sensitiveness to temperature. 

 Wherever dark pigment happened to be deposited in 

 the skin — and we know that in all animals it is apt to 

 be deposited in points and patches, as it were by 

 accident, or without any prophecy as to future uses — 

 the cutaneous nerves in its vicinity would be better 

 able to appreciate the difference between sun and 

 shade in respect of temperature, even though as yet 

 there were no change at all in these cutaneous nerves 

 tending to make them responsive to light."* 



Here we learn that the eye of the vertebrate, "per- 

 haps the most wonderful instance of refined mechan- 

 ism in nature," " had its origin in modifications of 

 the endings of the ordinary nerves of the skin." 



From this we would suppose that the eyes of verte- 

 brates would frequently be evolved, and in all sorts of 

 positions on the body, since the pigment is "apt to 

 be deposited in points and patches, as it were by 

 accident." These accidental deposits of pigment 

 would necessarily determine the positions of eyes. 

 * Darwin and After Darwin, p. 352. 



