272 FROM THE GREEKS TO DARWIN 



from science to literature retarded the demon- 

 stration of the evolution law by half a century. 



The 'unity of type' hypothesis, especially in 

 the structure of the back-boned or vertebrated 

 animals, which exercised such a potent influence 

 in Europe, was developed in Goethe's mind a 

 few years later, namely, in 1796; this was the 

 conception which formed the chief basis of his 

 idea of Evolution :^ 



Thus much, then, we have gained, that we may 

 assert, without hesitation, that all the more perfect 

 organic natures, such as fishes, amphibious animals, 

 birds, mammals, and man at the head of the list, were 

 all formed upon one original type, which varies only 

 more or less in parts which are none the less perma- 

 nent, and which stiU daily changes and modifies its 

 form by propagation. 



With him, this unity of type was broadly 

 based upon his own observations and was chiefly 

 a generalization of his own. This led him to a 

 correct explanation of half -developed or vestigial 

 structures, such as the os intermawillare, which 

 are among the strongest evidences of the law of 

 Evolution. He thoroughly understood the rela- 

 tions of the anatomy of man to that of lower 

 forms, and speaks of vestigial structures as fol- 



iGoethe: (Euvres d'histoire naturelle (French trans, by Mar- 

 tins), 1837, p. 66. 



