6 ARISTOTLE AS A BIOLOGIST 



of the Conservation of Energy, the final result of the 

 doctrine of the correlation of the physical forces, in 

 establishing which Rumford had led the way ; while 

 on the biological side he drew inspiration from the fact, 

 indicated by Aristotle, developed by Wolff and Milne- 

 Edwards, made into an aphorism by Von Baer, that as 

 the organism grows it grows continually from the simple 

 to the complex, from the homogeneous to a greater and 

 greater heterogeneity. 1 



But many years before Von Baer a greater than he had 

 enunciated the same truth, and had set it forth in even 

 plainer and better words. It was Goethe, in his Zur 

 ^Morphologic, 2 who laid it down as a law that ' the more 

 imperfect a being is, the more do its individual parts 

 resemble each other, and the more do these parts resemble 

 the whole. The more perfect the being is, the more dis- 

 similar are its parts. In the former case the parts are 

 more or less a repetition of the whole ; in the latter case 

 they are totally unlike the whole. The more the parts 

 resemble each other, the less subordination is there of one 

 to the other ; and subordination of parts is the mark of 

 high grade of organization.' 3 Now these words are found 

 in the Life of Goethe, by Lewes, Herbert Spencer's closest 

 friend. We can scarce avoid the inference that it may have 

 been the poet's insight and the poet's words, quite as much 

 as Von Baer's, that crystallized in his famous formula of 

 evolution. And the inference is confirmed by the fact 

 that, though it was to Von Baer that Spencer was after- 

 wards in the habit of ascribing the law, yet, on the first 



1 The ' law of differentiation ', or of ' organic progress ', was first 

 propounded by Spencer in his essay on Progress, its Law and Cause 

 (1857), where he argued that it was also the law of all progress what- 

 soever. 



2 1807 (written in 1795). Republished in Goethe's Werke, xxxvi, p. 7. 



3 Lewes, Life of Goethe (1855), 3rd ed. 1875, p. 358. 



