274 FROM THE GREEKS TO DARWIN 



naturalists will be to determine how, for instance, 

 cattle got their horns, and not for what they are 

 used." He thus, with Kant, felt the gap in the 

 lack of a natural explanation for the origin of 

 purposive structures. 



Goethe's theory of the causes of Evolution, so 

 far as formulated, had the spirit of Aristotle 

 combined with that of Buff on and Lamarck and 

 is beautifully expressed in the passage Haeckel 

 selects from his Metamorphosis of Animals 

 (1819): 



All members develop themselves according to eternal 



laws, 

 And the rarest form mysteriously preserves the prim- 

 itive type. 

 Form therefore determines the animal's way of life, 

 And in turn the way of life powerfully reacts upon 



all form. 

 Thus the orderly growth of form is seen to hold 

 Whilst yielding to change from externally acting 

 causes.^ 



In his Metamorphoses of Plants, published in 

 1790, we find Goethe's ideas of filiation or de- 

 scent clearly expressed. He here derives all 

 plants from a single original form, and all the 

 elaborate structures of the plant from the leaf. 



iThis contains the Aristotelian 'matter and form' notion, to- 

 gether with a perception of the factors of Lamarck (4th line) and 

 of Buffon (6th line). 



