ARISTOTLE AS A BIOLOGIST 17 



he throws no little poetry and still more of music into his 

 description of the nightingale's song. 1 



But let us now come, at last, to exemplify, by a few 

 brief citations, the nature and extent of Aristotle's zoologi- 

 cal knowledge. And here, brevity bids me choose between 

 two ways : either to deal with Aristotle's theories or 

 his facts, his insight or his erudition. The former are of 

 the highest possible interest to us, and their treatment 

 partly includes the latter. But it would take more than 

 all the time I have, to deal with any one of Aristotle's 

 theories of generation, for instance, or of respiration 

 and vital heat, or those still weightier themes of 

 variation and heredity, the central problems of biology, 

 or again the teleological questions of adaptation and 

 r design. 



Let me therefore confine myself, almost wholly, to a few 

 fragments out of his storehouse of zoological and embryo- 

 logical facts. 



Among the bloodless animals, as Aristotle called what 

 we call the Invertebrates, he distinguishes four great 

 genera, and of these the Molluscs are one. These are the 

 cuttle-fish, which have now surrendered their Aristotelian 

 name of ' molluscs ' to that greater group, which is seen 

 to include them with the shell-fish, or * ostracoderma ' 

 of Aristotle. These cuttle-fishes are creatures that we 

 seldom see, but in the Mediterranean they are an article 

 of food, and many kinds are known to the fishermen. 

 All, or wellnigh all, of these common kinds were known 

 to Aristotle, and his account of them has come down 

 to us with singular completeness. He describes their 

 form and their anatomy, their habits, their development, 

 all with such faithful accuracy that what we can add 

 to-day seems of secondary importance. He begins with 



1 H. N. x. 43 (29). 



c 



