38 
MEMOIR OP 
having been unjustly rejected.”* His great 
principle, and from which he never deviates, is 
the observation of facts ; comparing them, and 
endeavouring to discover the circumstances in 
which they agree to the greatest extent. 
He begins by laying down a great number of 
general propositions, or aphorisms, which must 
evidently have been derived from the careful 
observation of an immense number of phenomena. 
The following may be regarded as specimens 
taken from his first book on the description of 
the parts of animals : — 
“ Some parts are simple, and divided into 
similar particles ; while others are compound, and 
consist of dissimilar elements. 
“ The same parts in animals vary in form, pro- 
portion, 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 man- 
ners : thus, some reside on land, others in water ; 
and of the latter some breathe water and others 
air. 
“ Those parts which seize the food, and into 
which it is received, are found in all animals. 
The sense of touch is common to all,” &c. 
The following is the zoological system of 
Aristotle : — 
Red-blooded animals. 
Quadrupeds, serpents, birds, fishes, cetacea 
* Macgillivray’s lives of eminent zoologists. 
