rebuilding materials
drawn from the plants, which in their turn manufacture them, so to
speak, by a mysterious combination of those same inorganic materials.

Let us trace out the history of the Horse in another direction. After
a certain time, as the result of sickness or disease, the effect of
accident, or the consequence of old age, sooner or later, the animal
dies. The multitudinous operations of this beautiful mechanism flag in
their performance, the Horse loses its vigour, and after passing
through the curious series of changes comprised in its formation and
preservation, it finally decays, and ends its life by going back into
that inorganic world from which all but an inappreciable fraction of its
substance was derived. Its bones become mere carbonate and phosphate of
lime; the matter of its flesh, and of its other parts, becomes, in the
long run, converted into carbonic acid, into water, and into ammonia.
You will now, perhaps, understand the curious relation of the animal
with the plant, of the organic with the inorganic world, which is shown
in this diagram (Figure 3).

(FIGURE 3. Diagram showing material relationship of the Vegetable,
Animal and Inorganic Worlds.)

The plant gathers these inorganic materials together and makes them up
into its own substance. The animal eats the plant and appropriates the
nutritious portions to its own sustenance, rejects and gets rid of the
useless matters; and, finally, the animal itself dies, and its whole
body is decomposed and returned into the inorganic world. There is thus
a constant circulation from one to the other, a continual formation of
organic life from inorganic matters, and as constant a return of the
matter of living bodies to the inorganic world; so that the materials
of which our bodies are composed are largely, in all probability, the
substances which constituted the matter of long extinct creations, but
which have in the interval constituted a part of the inorganic world.

Thus we come to the conclusion, strange at first sight, that the MATTER
constituting the living world is identical with that which forms the
inorganic world. And not less true is it that, remarkable as are the
powers or, in other words, as are the FORCES which are exerted by living
beings, yet all these forces are either identical with those which exist
in the inorganic world, or they are convertible into them; I mean in
just the same sense as the researches of physical philosophers