propriate to itself.

Therefore, in seeking for the origin of protoplasm, we must eventually
turn to the vegetable world. A fluid containing carbonic acid, water,
and nitrogenous salts, which offers such a Barmecide feast to the
animal, is a table richly spread to multitudes of plants; and, with a
due supply of only such materials, many a plant will not only maintain
itself in vigour, but grow and multiply until it has increased a
million-fold, or a million million-fold, the quantity of protoplasm
which it originally possessed; in this way building up the matter of
life, to an indefinite extent, from the common matter of the universe.

Thus, the animal can only raise the complex substance of dead protoplasm
to the higher power, as one may say, of living protoplasm; while the
plant can raise the less complex substances--carbonic acid, water, and
nitrogenous salts--to the same stage of living protoplasm, if not to the
same level. But the plant also has its limitations. Some of the fungi,
for example, appear to need higher compounds to start with; and no known
plant can live upon the uncompounded elements of protoplasm. A plant
supplied with pure carbon, hydrogen, oxygen, and nitrogen, phosphorus,
sulphur, and the like, would as infallibly die as the animal in his bath
of smelling-salts, though it would be surrounded by all the
constituents of protoplasm. Nor, indeed, need the process of
simplification of vegetable food be carried so far as this, in order to
arrive at the limit of the plant's thaumaturgy. Let water, carbonic
acid, and all the other needful constituents be supplied except
nitrogenous salts, and an ordinary plant will still be unable to
manufacture protoplasm.

Thus the matter of life, so far as we know it (and we have no right to
speculate on any other), breaks up, in consequence of that continual
death which is the condition of its manifesting vitality, into carbonic
acid, water, and nitrogenous compounds, which certainly possess no
properties but those of ordinary matter. And out of these same forms of
ordinary matter, and from none which are simpler, the vegetable world
builds up all the protoplasm which keeps the animal world a-going.
Plants are the accumulators of the power which animals distribute and
disperse.

But it will be observed, that the existence of the matter of life
depends on the pre-existence of certain compounds; namely, carbonic
acid, water, and certain nitrogenous bodies. Withdraw