SERIAL ORGANIC EVOLUTION 241 



see, all species of animals vary only a certain distance 

 from their mean, and tend always to recur to the 

 average type. But granting even much wider 

 variations, it is almost impossible to conceive of any 

 selective processes, though acting for millions of 

 years, adequate to evolve a man from an amoeba. 



It seems to us that we must confine selective 

 evolution to the variations within a species, and 

 the establishment of the variations most fitted to 

 survive, and must conceive of serial evolution 

 from amoeba to man as an inevitable process 

 of development as accurate and unerring as the 

 growth of an acorn into an oak. The acorn does 

 not try experiments ; it does not first attempt to 

 be a honeysuckle, and then a turnip ; it is not 

 transmogrified by the influence of environment ; 

 in every case it becomes an oak. And so with the 

 first hypothetical protoplasm : it probably did not 

 try this and that variation ; it probably varied 

 along certain preordained lines, just as a growing 

 finger or tooth does, and became reptile, fish, 

 marsupial, ape, man. It is quite easy to under- 

 stand how each species may have been modified 

 by the selective action of environment (including 

 sexual selection) on its variations ; but it is very 

 difficult indeed, as we have said, to conceive of 

 variations great enough, and of selective action 

 stringent enough, to account for the tremendous 



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