CHAPTEK XIV. 

 GENEKATION AND DEVELOPMENT. X 



Most of the important researches made by Aristotle on 

 generation and development are described in his Generation 

 of Animals, one of the most remarkable works ever written, 

 and the one most entitling him to be included amongst 

 the greatest thinkers of all time. Even those who have 

 minimized the value of his labours and have criticized his 

 works adversely have often been forced to comment favour- 

 ably on many parts of his Generation of Animals. His 

 History of Animals, which rivals his Generation of Animals 

 in greatness, is remarkable for the vast amount of information 

 which it contains, but the Ge?ieration of Animals astonishes 

 the reader by its deep, philosophical reasoning, and furnishes 

 evidence of a powerful intellect grappling with obscure 

 embryological problems. 



In his Generation of Animals, he proposes some abstruse 

 questions, and attempts to solve them in a way which is 

 masterly, considering the slender means of investigation at 

 his disposal. Some of these questions had been considered 

 before his time, but not efficiently. Aristotle also did a 

 great deal of original work (considered already in Chapter 

 xi.) on the generative organs ; nothing, he says, had been 

 previously determined about these.* 



He discusses an opinion, held by some philosophers and 

 based mainly on the observed similarity between young 

 animals and their parents, that the sperm {oTrep/xa) was 

 derived from all parts of the body.t He rejects this opinion, 

 and, in G. A. i. c. 18, adduces arguments against it, of which 

 the following are the most important : — 



(1) Children have nails, hair, &c., no part of which could, 

 he believed, be derived from the parents. 



(2) Children often resemble grand-parents or other 

 ancestors, from whom he believed they could not derive 

 anything, e.g., a daughter of an ^Ethiopian and a woman of 

 Elis was not black, but the son of this daughter was. 



* G. A. i. c. 1, 115a. f Ibid. i. c. 17, 7216 



