MEMOIR OF ARISTOTLE. 
107 
for the purpose of distinctive description — calling 
those animals which have red blood bxtfM, and those 
which have it not red oumtuu ; and thus he esta- 
blishes a fundamental natural division, answering to 
the red-blooded and white-blooded animals of mo- 
dern zoology. Another distribution of the several 
classes is into those which have blood, and those 
which have not; — among the former are man, vivi- 
parous and oviparous quadrupeds, birds, fishes, ceta- 
ceous animals, and serpents ; while the latter com- 
prise those naturally divisible into segments, as in- 
sects, those of a soft substance throughout, as cuttle- 
fish, &c. those having a comparatively soft shell, as 
lobsters, &c. and those which have a hard shell, as 
oysters, &c. 
In examining the component members of animals 
in general, it has been already observed, that Aris- 
totle selected man as a standard of comparison, al- 
leging as a reason, that we are more familiar with 
the human form than w'ith any other : hence it fol- 
lows, as a necessary consequence, that viviparous 
animals, birds, reptiles, and fishes, would respec- 
tively come next in succession ; and this order he 
actually observes in making his classification. Some 
have found fault with this arrangement, on the 
ground of its commencing with animals of a more 
complicated instead of those of a more simple struc- 
ture, but there seems no good cause for the objec- 
tion ; and it is no mean encomium on the Stagirite 
to observe, that the same principle of arrangement 
