398 
ON THE STRUCTURE AND HABITS 
properties, requires to be studied in this manner before we can obtain a correct 
knowledge of its Nature. These two conditions of an object are constantly 
considered in Natural History. As an instance, let us take a plant: I may 
know its colour, size, form, weight, and the place in which it gro.Ws, but unless 
I know the changes which are undergone by the plant with regard to its size, 
form, weight, colour, and so on, I cannot be said to know its natural history. 
Although these remarks will extend to but a small portion of the objects of 
Natural History, yet a few observations on the relation they bear to other objects 
in Nature will not be unnecessary. 
All objects in Nature are arranged in three great divisions, which may be 
respectively represented by a mineral, a plant, and an animal; and the collections 
of objects in Nature bearing the characters of these things are called the mineral, 
vegetable, and animal kingdoms. Now the basis of every thing in Nature is 
matter, and the only difference between a stone and a plant is, that the latter 
form of matter is endowed with properties the former does not possess. Whilst 
the matter, again, of which an animal is constituted differs from the matter of 
the plant, in being endowed with properties denied to the plant. The Mineral 
Kingdom, then, the lowest of these divisions, is universally subject to what are 
called the laws of matter, or physical laws, but when we ascend to the Vegetable 
Kingdom we shall find a new property added to matter, which to a great extent 
controls and modifies the mere physical laws to which minerals are subject; this 
is the principle of vitality. On ascending higher, and entering the Animal King¬ 
dom, we find other properties added to matter which exercise a controlling 
influence over the properties it possesses as a mineral or a plant. The laws which 
minerals obey in common with plants and animals are called physical laws; the 
laws which the principles of vitality in plants obey, and which they have in 
common with animals, are called the laws of organic life, or organic laws ; whilst 
the laws which the animal machine obeys, distinguished from the two others, are 
called the laws of animal life. Each of these departments comprehends an almost 
countless number of objects, and the attention of scientific men has been directed 
at all times to the means of distinguishing these from each other. Hence have 
resulted those systems of classification, the permanence of which being secured 
by the art of printing, have been gradually improving up to the present day. In 
this manner upwards of 80,000 plants have been described, so that a botanist 
can easily distinguish one from another. In the Animal Kingdom, 20,000 
species of insects alone have been described as indigenous to Britain. Our know¬ 
ledge of the objects of Nature is thus every day increasing, and we are furnished 
with the means of deducing those great principles or laws by which the Deity 
upholds all things, and by a knowledge of which Man can alone expect to ensure 
