FRANCIS W1LLUGHBY. 
29 
isted from a remote period among civilized nations. 
But, carried to this extent only, Natural History 
consists in mere amusement, and the books and 
pictures serving merely this purpose, may afford 
relaxation from more important studies, or at 
best supply the naturalist engaged in the forma- 
tion or study of a system with useful descriptions 
of such individual creatures as may be inacces- 
sible to his own observation. 
Yet, in nearly this state did Natural History 
continue till the time of Aristotle, at least among 
such portions of mankind as were unacquainted 
with the Scriptures, and for many ages after him. 
The scientific pursuit of any department of 
Natural History supposes classification, or the 
arrangement of its various objects into those 
divisions called genera and species, an arrange- 
ment founded on some selected points of agree- 
ment between those objects. 
The most general, because the most obvious 
point of agreement, would be a complete identity 
amongdifferentindividuals. Thus, to take a familiar 
illustration from ornithology, — a certain bird being 
called a crow, the same name or noun is given to 
every other crow in the flock, which general 
name or noun is technically called the genus. 
Among the different tribes of'creatures, however, 
the resemblance, though very close, is not com- 
plete, the difference sometimes consisting in but 
few subordinate variations, sometimes only in 
one ; in such cases, the naturalist considers to 
which genus any given instance of variation 
