ARISTOTLE. 43 



follows that he is responsible for them. Bearing in 

 mind the curious history of the manuscripts of his trea- 

 tises, we shall find it far more reasonable to conclude 

 that such errors crept in during the process of correction 

 and restoration, by men apparently ignorant of biology, 

 than that (to take only one case) an observer who had 

 distinguished the cetacea from fishes and had detected 

 their hidden mammae, discovered their lungs, and recog- 

 nized the distinct character of their bones, should have 

 been so blind as to fancy that the mouth of these 

 animals was on the under surface of the body. 



That Aristotle made hasty generalizations is true ; 

 but it was unavoidable. Biology was in so early a stage 

 that a theory had often of necessity to be founded on 

 a very slight basis of facts. Yet, notwithstanding this 

 drawback, so great was the sagacity of this philosopher, 

 that many of his generalizations, which he himself pro- 

 bably looked upon as temporary, have held their ground 

 for twenty centuries, or, having been lost sight of, have 

 been discovered and put forward as original by modern 

 biologists. Thus "the advantage of physiological 

 division of labour was first set forth," says Milne- 

 Edwards, "by myself in 1827;" and yet Aristotle had 

 said l that " whenever Nature is able to provide two 

 separate instruments for two separate uses, without the 

 one hampering the other, she does so, instead of acting 

 1 "De Part. Anim.," iv. 6. 



