ioo A Factor in Evolution 



of natural selection, as has been seen, and so keeps alive 

 the creatures which have no instincts for the performance 

 of the actions required, nevertheless does not subserve the 

 utilities which the special instincts do, nor prevent them 

 from having the selective value of which Romanes speaks. 

 Accordingly, on the more general definition of intelligence, 

 which includes in it all conscious imitation, use of parental 

 instruction, and that sort of thing, no less than on the 

 more special definition, we still find the principle of 

 natural selection operative ' (from an earlier page). 



3. This completely disposes of the Lamarckian factor so 

 far as two lines of evidence for it are concerned. First : 

 the evidence drawn from function, ' use and disuse,' is 

 discredited, since by organic selection the reappearance, 

 in subsequent generations, of the modifications first secured 

 in ontogenesis, is accounted for without the inheritance 

 of acquired characters. So also the evidence drawn from 

 paleontology, which cites progressive variations in the same 

 lines as resting on functional use and disuse. Second : 

 the evidence drawn from the appearance of ' determinate 

 variations ' ; for by our principle we have the continued 

 selection and preservation of variations in definite lines in 

 phylogeny without the inheritance of acquired characters. 



4. But this is not preformism in the old sense ; since tJie 

 accommodations made in ontogenetic development, which 

 ' set ' the direction of evolution, are novelties of function in 

 whole or part (although they utilize congenital variations of 

 structure). It is often by the exercise of novel functions 

 that the creatures are kept alive to propagate and thus to 

 produce further variations of structure which may in time 

 make the whole function, with its adequate structure, con- 

 genital. Romanes' arguments from 'partial co-adaptations' 



