but of all preceding study in this department. It is evident that even
then much had been done, and, in allusion to certain peculiarities of the
human frame, which he does not describe in full, he refers his readers to
familiar works, saying, that illustrations in point may be found in
anatomical text-books.[1]

[1] See Aristotle's _Zoölogy_, Book I., Chapter xiv.

Strange that in Aristotle's day, two thousand years ago, such books should
have been in general use, and that in our time we are still in want of
elementary text-books of Natural History, having special reference to the
animals of our own country, and adapted to the use of schools. One fact in
Aristotle's "History of Animals" is very striking, and makes it difficult
for us to understand much of its contents. It never occurs to him that a
time may come when the Greek language--the language of all culture and
science in his time--would not be the language of all cultivated men. He
took, therefore, little pains to characterize the animals he alludes to,
otherwise than by their current names; and of his descriptions of their
habits and peculiarities, much is lost upon us from their local character
and expression. There is also a total absence of systematic form, of any
classification or framework to express the divisions of the animal kingdom
into larger or lesser groups. His only divisions are genera and species:
classes, orders, and families, as we understand them now, are quite
foreign to the Greek conception of the animal kingdom. Fishes and birds,
for instance, they considered as genera, and their different
representatives as species. They grouped together quadrupeds also in
contradistinction to animals with legs and wings, and they distinguished
those that bring forth living young from those that lay eggs. But though a
system of Nature was not familiar even to their great philosopher, and
Aristotle had not arrived at the idea of a classification on general