ASPECTS OF KINETIC EVOLUTION 221 



maintain and extend the normal organization of the species. 

 The individual plant gains no advantage from cross-fertilization ; 

 the advantage appears only when the results are viewed from 

 the standpoint of the species. 



FITNESS BY CORRELATION OF VARIATIONS. 



No one has appreciated more keenly than Darwin himself the 

 limitation of his doctrine of selection in the way of providing 

 new characters of fitness on which selection could work. He 

 continued with persistence the search for adaptive significances 

 of characters, and supplemented his discoveries in that direction 

 by the hypothesis of the correlation of variations. This assumes 

 that the characters which are being developed by selection carry 

 with them the development of other characters, some of which 

 may remain useless while others attain utility and thus become 

 in turn the objects of selective education. It is as though charac- 

 ters were fastened together in groups like chairs and tables so 

 that they could be hitched along first by one leg and then by 

 another. 



Instances of correlation between characters have been found, 

 and the suggestion gains somewhat from the fact that mutations 

 of independent origin often show close similarity although dif- 

 fering from the parent type in numerous characters instead of in 

 one only. Such a mutation might receive a selective advantage 

 for one character, though the others would be preserved at the 

 same time. Nevertheless, this suggestion would be subject to 

 the same objection as the mutation theory as a whole, that the 

 phenomena are abnormal and do not afford a true indication of 

 the method of evolution in nature, for there the diversity appears 

 not to be of the mutation type, but shows unlimited intergrada- 

 tions of all the characters, as though to give absolute freedom 

 in the making of truly constructive combinations. 



Correlations between different parts and tissues undoubtedly 

 exist, but we may believe that they are brought about by normal 

 evolutionary processes instead of supposing that characters have 

 been tied up in arbitrary groups or bundles, which only explains 

 one difficulty by imagining others still more mysterious. Such 

 a character-complex would be, in effect, a suborganic organiza- 



