112 ORGANIC EVOLUTION — THE FACTORS 



He forgot also that survival does not iu general depend 

 on superiority in any one quality, but on a general 

 average of superiority in all essential qualities, and 

 therefore, since the fit survive and the uafit perish, 

 there may be, if the struggle for existence is sufficiently 

 severe, interbreeding notwithstanding, evolution in all 

 the essential qualities, by the accumulation of inborn 

 variations alone. As formerly he argued that the 

 evolution by the accumulation of inborn variations 

 alone of all the numerous qualities necessary for survival 

 is, owing to their multiplicity, impossible ; so now he 

 argues that the evolution of any particular quality — e. g. 

 fighting power — nay, even of any structure — e. g. horns 

 ^-by the . accumulation of inborn variations alone is 

 impossible, owing to the multiplicity of the structures 

 implicated in the evolution. 



Leaving for a moment Mr. Spencer's theoretical 

 objections, let us consider some facts of nature which 

 are within the cognizance of every one. The children 

 of the same parents usually differ appreciably when 

 grown in their physical powers, as also do the individug,! 

 members of a litter of puppies, or the individual 

 chickens hatched from a nest of eggs. These variations 

 must be due to inborn variations, not to variations 

 acquired by the parents and transmitted to the off- 

 spring, for, at any rate as regards the puppies and 

 chickens, the circumstances attending the genesis of 

 each individual in the litter or brood are such as 

 practically to preclude the possibility of any one differ- 

 ing from the others except through differences in inborn 

 variations, since in each case all the spermatozoa and 

 ova, aiid the organisms which arose from them, were 

 circumstanced exactly alike as regards the parent 

 organisms ; in other words, if acquired variations are 

 transmissible, each individual under the circumstances 

 must have acquired the same variations, and therefore 



