ORGANIC EVOLUTION — THE FACTORS 81 



this respsct, other things equal, must therefore have 

 contributed, as in the horns of deer, to the ability to 

 leave offspring, and thus led to the evolution of spurs 

 — an evolution slow at first, but afterwards more rapid 

 as the spurs increased in size and importance. 



Again and again in the literatvire of biology we may 

 find objections to the theory of evolution by the 

 accumulation of inborn variations alone, founded on 

 the assumption that such evolution must depend on 

 the perpetuation andaccentuationof abnormal variations ; 

 that is, of variations which far transcend the specific 

 mean, or which are entirely new structures, and there- 

 fore practically speaking deformities, and which occur 

 in only one individual in a thousand, or in ten thousand, 

 or in ten million. Of course if such an assumption is 

 made, it is easy enough to demolish the theory 

 founded on it, and then to declare that, since evolution 

 certainly has occurred, and since the accumulation of 

 inborn traits is inadequate to account for it, it must be 

 due in part at least to the accumulation of acquired 

 traits. Lord Salisbury made this assumption in his 

 speech delivered before the British Association at 

 Oxford in 1894, and going beyond Mr, Spencer, came 

 to the conclusion, remarkable in a President of that 

 learned body, which has done so nmch to elucidate 

 the sciences of Paleontology and Embryology, from which 

 are drawn decisive proofs of the theory, that on this 

 account, and because mathematicians deny that the 

 globe has been habitable for so long a period as, in 

 the opinion of geologists, is necessary for the evolution 

 of highest life from lowest life, it (the theory of 

 evolution) must be taken as "not proven." 



It is not too much to say that Lord Salisbury 

 entirely mistook the jjoint at issue. It is not now 

 doubted by the majority, the immense majority of 

 those acquainted with the facts, that the organic world 



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