14 INTRODUCTORY. 



different language, e. cj., he tells us that his Selache are 

 cartilaginous, or that they are ovoviviparous, in many diffe- 

 rent passages, most of his statements about his homoso- 

 meria in the History of Animals are repeated in his Parts 

 of Animals, and many parts of the subject-matter of his 

 Generation and Destruction are to be found in his remaining 

 works. 



In his zoological works are many passages which the 

 context does not explain, and quite one-half of the animals 

 mentioned by him are not described in such a way as to 

 enable them to be identified. The reason for this is that 

 in many cases the animals are mentioned merely for the 

 purpose of illustrating general statements. On the other 

 hand, several passages which are not explained by their 

 contexts are made clear in one or more passages of the same 

 or a different work, e.g., that in his History of Animals, 

 i. c. 5, s. 7, which asserts that animals walk >t»Ta ^idfxsrpov, 

 is fully explained in his Progression of Animals, c. 14. It 

 is necessary, in fact, to study many passages in several 

 of his treatises, in order to understand his views on most 

 scientific subjects, and, it should be mentioned, some of 

 these passages are not consistent. Two works, the Zoica 

 and Anatomica, to which he sometimes refers, would have 

 thrown light on difficult passages in his extant zoological 

 works. Those two works, however, have not been recovered. 



It has often been stated that in his zoological works 

 Aristotle has borrowed from many writers without acknow- 

 ledgment. This charge seems to be substantially true, 

 although he specifically mentions Anaxagoras, Empedocles, 

 Democritus of Abdera, Alcmseon, ©ieSy^ue of Apollonia, 

 Herodotus, Syennesis of Cyprus, Polybus, and a few others. 

 The comment made by Cuvier and Valenciennes, when 

 speaking of Aristotle's work in connection with fishes, is not 

 unfair. They say : " It is true that, by a practice only too 

 common in our own time, Aristotle scarcely mentions other 

 authors, except those whom he wishes to refute, and he has 

 been charged even with ingratitude to Hippocrates, whose 

 name he does not mention, although he must have borrowed 

 from him more than one idea. As regards the rest, we do 

 not think that he has done much wrong to the ichthyo- 

 logists, if any, who preceded him. The fragments pre- 

 served by Athenaeus, which we can attribute to them, do 

 not show that they treated their subject methodically or 

 carefully, and everything makes us believe that it was 



