72 FROM THE GREEKS TO DARWIN 



or type in certain classes of animals, and consid- 

 ered rudimentary organs as tokens whereby Na- 

 ture sustains this unity; he rightly conceived of 

 life as the function of the organism, not as a sep- 

 arate principle ; he anticipated Harvey's doctrine 

 of epigenesis in embryonic development ; he fully 

 perceived the forces of hereditary transmission, 

 of the prepotency of one parent or stock, and of 

 atavism or reversion; he saw the fundamental 

 difference between animals and plants, and dis- 

 tinguished the organic or living world from the 

 inorganic or lifeless world. He also perceived the 

 'compensation of growth' principle as shown in 

 a passage^ of his upon the origin of horns: 



Having now explained the purpose of horns, it 

 remains to see the necessity of matter, by which Na- 

 ture gave horns to animals. . . . We see that Nature 

 taking away matter from the front teeth [alluding 

 to the ruminants] has added it to the horns. 



Aristotle was familiar with both the proto- 

 Lamarckian and the proto-Darwinian hypothe- 

 ses of his predecessors. The former doctrine, now 

 known as adaptation through the transmission 

 of acquired characters, Aristotle traced back to 



1 This passage does not appear in the Historia Animalium^ in 

 which the treatment is purely anatomical, physiological, and zo- 

 ological, rather than interpretative or philosophical. Aristotle's 

 interpretations and discussions are to be found in his Physica, in- 

 cluding the De Generatione. See Parts and Progressive Motions 

 of Animals, Book III, Chap. II. 



