NATURAL SELECTION 



It must be borne in mind that this is a purely 

 hypothetical illustration, which does not pre- 

 tend to give a complete account of the complex 

 process. I have no idea that the differentiation 

 between antelopes and buffaloes, or between 

 lions and leopards, was accomplished in any such 

 straightforward way as this. But while unduly 

 simplifying the case, the illustration is undoubt- 

 edly sound in principle. No doubt the lion is 

 so strong and so swift because only the strong- 

 est and swiftest lions have been able to prey at 

 once upon buffaloes and upon antelopes. No 

 doubt the antelope is so swift and so timid 

 because only the swiftest and most quickly 

 frightened antelopes have been enabled to 

 get away from the lion, and to propagate their 

 kind. And no doubt in the process above de- 

 scribed, we get a partial glimpse of some of the 

 essential incidents in the past careers of these 

 races. 



All the foregoing illustrations unite in enfor- 

 cing the conclusion that the direct and indirect 

 effects of natural selection are by no means lim- 

 ited to slight or superficial changes in organ- 

 isms. The student of physiology well knows 

 that no change, however seemingly trivial, which 

 ensures the survival of the organism in its fierce 

 struggle for existence, can fail in the long run 

 to entail so many other changes as to modify, 

 more or less perceptibly, the entire structure. 

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