58 ARISTOTLE. 



observation and laborious investigation, is calculat- 

 ed to afford material aid to the modern student. 

 To him more recent productions are the only safe 

 guides; nor is it until he has studied them, and 

 interrogated nature for himself, that he can derive 

 benefit from the perusal of the treatise which we now 

 proceed to examine. 



The first book contains a brief description of the 

 parts of which the bodies of animals are composed. 

 The introduction consistsof general propositions; of 

 which we shall present a few of the more remark- 

 able as a specimen. 



Some parts, he observes, are simple, and divided 

 into similar particles ; while others are compound, 

 and consist of dissimilar elements. The same parts 

 in different animals vary in form, proportion, and 

 other qualities ; and there are many creatures which, 

 although they have the same parts, have them in 

 different situations. Animals differ in their mode 

 of living, actions, and manners : thus, some reside 

 on land, others in water; and of the latter some 

 breathe water, others air, and some neither. Of 

 aquatic animals, some inhabit the sea, others the 

 rivers, lakes, or marshes. Of those which live in 

 the sea, some are pelagic, others littoral, and others 

 inhabit rocks. Of land-animals, some respire air, 

 as man ; others, although they live on the land and 

 obtain their food there, do not breathe air, as wasps, 

 bees, and other insects. 



We know no animal, says he, that flies only, as the 

 fish swims ; for those which have membranous wings 

 walk also; and bats have feet, as have seals, al- 

 though imperfect. But some birds have the feet 

 weak ; in which case the defect is compensated by 



