ARISTOTLE 



697 a 15 (c) Intermediate Creatures: 



Cetacea. 

 Seals and Bats. 

 Ostrich. 



697 b 27 Conclusion. 



Method of A glance at the summary will show clearly the 

 BwiUon. order of subjects which Aristotle lays (ΙοΛντι in the 

 first book to be followed in a treatise such as the 

 one in which he is enffaged. 



First, (A) to describe the parts of animals as they 



are observed to be ; and 

 then, (B) to give an account of their causes, and 



their formative processes.* 

 Under (A) the order of preference is to be : €rst, 

 the parts (1) common to all animals -, (2) 

 where necessary, those common to a 

 group of animals only ; and lastly, (3) in 

 exceptional instances, those peculiar to a 

 single species. 

 Also, it will be seen how Aristotle ΛVorks out this 

 scheme in the three books which folloAV. Before 

 considering that, however, we should notice that 

 Aristotle has a great deal to say about the correct 

 classification of animals — or rather, against the in- 

 correct classification of them. Chiefly, he inveighs 

 against the method of dichotomy ; and his chief 

 objection to it is a simple and effective one — that it 

 does not work. It forces us to assign to each species 

 one distinguishing mark, and one only (642 b 21 — 

 64•3 a 24). And it cuts off kindred species from each 

 other on the strength of some quite subordinate 



" De partihus is concerned chiefly with the causes and less 

 * with the processes. 



18 



