ARISTOTLE 3 



structure of animals. Owing to the importance which 

 Aristotle ascribed to the final cause this work became really 

 a treatise on the functions of the parts, a discussion of the 

 problems of the relation of form to function, and the 

 adaptedness of structure. 



Aristotle was quite well aware that each of the big groups 

 of animals was built upon one plan of structure, which 

 showed endless variations " in excess and defect " in the 

 different members of the group. But he did not realise that 

 this fact of community of plan constituted a problem in 

 itself. His interest was turned towards the functional side of 

 living things, form was for him a secondary result of 

 function. 



Yet he was not unaware of facts of form for which he 

 could not quite find a place in his theory of organic form, 

 facts of form which were not, at first sight at least, facts of 

 function. Thus he was aware of certain facts of" correlation," 

 which could not be explained off-hand as due to correlation 

 of the functions of the parts. He knew, for instance, that all 

 animals without front teeth in the upper jaw have cotyledons, 

 while most that have front teeth on both jaws and no horns 

 have no cotyledons (Dc Gen., ii. 7)- 



Speaking generally, however, we find in Aristotle no 

 purely morphological concepts. What then does morphology 

 owe to Aristotle? It owes to him, first, a great mass of facts 

 about the structure of animals ; second, the first scientific 

 classification of animals; 1 third, a clear enunciation of the fact 

 of community of plan within each of the big groups ; fourth, 

 an attempt to explain certain instances of the -correlation of 

 parts; fifth, a pregnant distinction between homogeneous and 

 heterogeneous parts ; sixth, a generalisation on the succession 

 of forms in development; and seventh, the first enunciation of 

 the idea of the EcJielle dcs etres. 



(i) What surprises the modern reader of the Historia 

 Animalinin perhaps more than anything else is the extent 

 and variety of Aristotle's knowledge of animals. He 



1 On Aristotle's forerunners, see R. Burckhardt, "Das koi'sche 

 Tiersystem, eine Vorstufe des zoologischen Systematik des Aristoteles." 

 Verh. Naturf. Ges. Basel, xx., 1904. 



