HISTORICAL OR COMPARATIVE METHOD 65 



Descartes.^ The Histoire Naturelle inclines to some 

 theory of evolution, especially in the later volumes. At 

 first Buffon teaches that species are fixed and wholly 

 independent of one another ; some years later he is ready 

 to believe that all quadrupeds may be derived from some 

 forty original forms, while in a third and subsequent 



Georges Louis Leclerc, Comte de Buffon. 



passage he puts the question whether all vertebrates 

 may not have had a common ancestor. He does not 

 shrink from saying" that one general plan of structure 



• For an account of other early hypotheses of the same kind 

 the reader may refer to Edward Clodd^s Pioneers of Evolution, 



