1TS GENERAL NATURE AND ADVANTAGES. 95 
matter, whether ponderable or imponderable, whether 
the objects we contemplate are visible to the eye, 
palpable to the touch, or invisible agents known 
only by their effects. 
(43.) But the human mind, limited in its powers, 
is compelled to relinquish the study of universal 
nature, and to confine its researches to distinct 
portions. Hence has originated the necessity of in- 
stituting those numerous divisions in natural phi- 
losophy, respectively assigned to the astronomer, 
the chemist, and the physiologist. These pursuits, 
like others of a subordinate nature, are no longer 
considered as forming a part of natural history, 
properly so called; although, in a general sense, 
they strictly and exclusively emanate from the study 
of nature. Geology, in like manner, separates itself 
as a distinct department; not because it merely 
embraces terrene objects, but because it relates more 
to the situation, than to the analysis, of the com- 
ponent parts of our globe. Its chief business is to 
trace and explain the changes and revolutions which 
have happened to the earth; but not, like mineralogy, 
to determine the primary elements of which it is 
composed. Natural history, thus restricted, may, in 
a philosophic sense, be termed the study of ponder- 
able matter, or, to state this definition in more popular 
language, it is the province of natural history to 
embrace all that concerns the three great divisions 
or kingdoms of nature,—the animal, the vegetable, 
and the mineral. Such is the view which, in common 
with some of the highest authorities, we propose to 
take of this science. And although our subsequent 
remarks will chiefly relate to the animal kingdom, 
