INADEQUACY OF NATURAL SELECTION, ETC. G47 



of skin-discriminativeness which I contend is not thus accounted 

 for. Hut 1 deny that either the general sensitiveness or the 

 special sensitiveness results from natural selection ; and I have 

 years ago justified the first disbelief as I have recently the second. 

 In &quot; The Factors of Organic Evolution &quot; (Essays, 454 8), I 

 have given various reasons for inferring that the genesis of the 

 nervous system cannot be due to survival of the fittest ; but that 

 it is due to the direct effects of converse between the surface and 

 the environment ; and that thus only is to be explained the 

 strange fact that the nervous centres are originally superficial, and 

 migrate inwards during development. These conclusions I have, 

 in the essay Mr. Wallace criticizes, upheld by the evidence which 

 blind boys and skilled compositors furnish ; proving, as this does, 

 that increased nervous development is peripherally initiated. Mr. 

 Wallace s belief that skin-sensitiveness arose by natural selection, 

 is unsupported by a single fact. He assumes that it must have 

 been so produced because it is all-important to self-preservation. 

 My belief that it is directly initiated by converse with the environ 

 ment, is supported by facts ; and I have given proof that the 

 assigned cause is now in operation. Am I called upon to abandon 

 my own supported belief and accept Mr. Wallace s unsupported 

 belief ? I think not. 



Referring to my argument concerning blind cave-animals, 

 Professor Lankester, in Nature of February 23, 1893, writes : 



&quot; Mr. Spencer shows that the saving of ponderable material in the sup 

 pression of an eye is but a small economy : he loses sight of the fact, however, 

 that possibly, or even probably, the saving to the organism in the reduction 

 of an eye to a rudimentary state is not to be measured by mere bulk, but by 

 the non-expenditure of special materials and special activities which are con 

 cerned in the production of an organ so peculiar and elaborate as is the verte 

 brate eye.&quot; 



It seems to me that a supposition is here made to do duty as a 

 fact ; and that I might with equal propriety say that &quot; possibly, 

 or even probably,&quot; the vertebrate eye is physiologically cheap : 

 its optical part, constituting nearly its whole bulk, consisting of 

 a low order of tissue. There is, indeed, strong reason for con 

 sidering it physiologically cheap. If any one remembers how 

 relatively enormous are the eyes of a fish just out of the egg a 

 pair of eyes with a body and head attached ; and if he then 

 remembers that every egg contains material for such a pair of 

 eyes ; he will see that eye-material constitutes a very considerable 

 part of the fish s roe ; and that, since the female fish provides 

 this quantity every year, it cannot be expensive. My argument 

 against Weismann is strengthened rather than weakened by con 

 templation of these facts. 



Professo- Lankcster asks my attention to a hypothesis of his 

 42 



