Evidences of Theory of Natural Selection. 291 



presents it ; but he also conceived a purely fictitious 

 inversion of this truth, and wrote an essay to prove a 

 statement which all the instincts in the animal kingdom 

 unite in contradicting. 



This example will serve to show, in a striking 

 manner, not only the distance that we have travelled 

 in our interpretation of organic nature between two 

 successive editions of the Encyclopaedia Britannica^ but 

 also the amount of verification which this fact furnishes 

 to the theory of natural selection. For, inasmuch 

 as it belongs to the very essence of this theory that all 

 adaptive characters (whether instinctive or structural) 

 must have reference to their own possessors, we find 

 overpowering verification furnished to the theory by 

 the fact now before us — namely, that immediately prior 

 to the enunciation of this theory, the truth that all 

 adaptive characters have reference only to the species 

 which present them was not perceived. In other 

 words, it was the testing of this theory by the facts 

 of nature that revealed to naturalists the general law 

 which the theory, as it were, predicted — the general 

 law that all adaptive characters have primary reference 

 to the species which present them. And when we 

 remember that this is a kind of verification which is 

 furnished by millions of separate cases, the whole 

 mass of it taken together is, as I have before said, 

 overwhelming. 



It is somewhat remarkable that the enormous im- 

 portance of this argument in favour of natural 

 selection as a prime factor of organic evolution has 

 not received the attention which it deserves. Even 

 Darwin himself, with his characteristic reserve, has 

 not presented its incalculable significance ; nor do I 



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