crystalline form, they offer a like mode of
composition.

Do not these facts betray the action of a
force which directs the atoms and subjects them
to its law? a sort of primordial, elementary
force, animating all matter, sometimes causing
a simple aggregation of the molecules, sometimes
arranging them in determinate order, according
to the conditions in which they happen to be
placed. This force, M. Hénant informs us, is
called "la force physico-chimique;" which does
not in the least help us to understand what it is,
or whence derived. All we can say is, that it must
originate with the Great Artificer of all things.

Advancing with his subject, our author passes
on to organic matter, where he finds himself in
the presence of new phenomena. Here he
confidently rushes on, where abler men, without
exactly fearing to tread, proceed with very
cautious footsteps. Perhaps the temerity may
be more apparent than real. Organic matter,
he allows, is identically the same as inorganic.
It is the same matter which in turn makes a
part of minerals, vegetables, and animals; the
same which forms the soil, the leaves, the fruits,
the arteries, and the brain—thus circulating
through a hundred different organisations. This
agrees with the teaching, that the matter of our
bodies is exactly that of inorganic nature, and
that there is no substance in the animal tissues
which is not primarily derived from the rocks,
the water, and the air.

But then comes the question of Vital Force.
We know that there is a vital force. Consider
a tree, and remember that it sprung from a
seed; that from that seed there simultaneously
issued, both a root, which of its own accord
tended downward, and a stem, which sprouted
upward; and then, that this root, by the nature
of its tissue, is essentially fitted to imbibe the
moisture of the earth, while the leaves are
equally suited to act as lungs, which is the part
assigned to them in the vegetable. You mark
the appropriation of the tissue to its object, of
the texture of the organ to its function.

Observe now the form of the tree, and you
will be struck with its persistence. While the
tree is being developed, its form remains
constant at every period of its life. During the
whole of its existence, sometimes very long—
and, what is more, during a progressive increase
—the form of the tree is faithfully preserved.
No change takes place in the shape of its
branches, its leaves, its flowers, or its fruits.
An ash never disguises itself as an elm; an olive
never assumes the costume of an orange-tree.
Do men gather grapes off thorns, or figs off
thistles? An oak-leaf is always the leaf of an
oak, so long as that oak continues to live. It
constantly displays an oak-leaf's colour, shape,
nature, and dimensions. Whether the tree be
young or old, and even if the matter of which
it is constituted have been repeatedly renewed,
its form suffers no modification.

The limit of stature is no less remarkable than
the persistence of form. Take the poplar and
the reed, though of quite different build; neither
exceeds a certain height. Look at a field of
wheat; the level of the surface is scarcely broken
by any inequality in the length of the stems.
Finally, the duration of vegetable life, the limit
of its extension in time, is not less determinate
than the limit of its extension in space. There
are annual, biennial, and perennial plants; perennials
even seem to have each their own special
span of life. Some exist for tens, others for
hundreds, others for thousands of years.

Nevertheless, let chemists analyse the diverse
specimens of vegetable organisation, and they
will discover the same material elements, namely,
those which constitute the world of minerals.
The two kingdoms are constantly interchanging
the same materials; the same oxygen, the same
hydrogen, the same carbon, alternate, make part
of minerals and vegetables. It is the same
matter, so to speak, which is run into different
moulds, clothes itself in divers colours, offers
various outlines and dimensions. "Molecular
forces determine the form which the vital energy
will assume. In one case, this energy is so
conditioned by its atomic machinery, as to
result in the formation of a cabbage; in another
case, it is so conditioned as to result in the
formation of an oak." But the very same
carbon may have entered into the chalk, into a
fagot, into a flower, or into a fruit.

Like phenomena are more marked and evident
in the organisation of animals. The persistence
of form is more distinctly traced, the mutations
of matter are more completely apparent, the
phases of life more strongly characterised.
Experiments made by mixing madder with an
animal's food, prove that even in solid bone there
is continual change of its constituent matter
during the formation, the development, and the
life of bones. The same takes place in every
part of an animal's body. Veins, arteries,
muscles, nerves, are incessantly undergoing
renovation. All those organs offer the spectacle
of a continual change of the matter which
constitutes their substance. An accident to the
skin, after a certain time, disappears through
this reparative process. During youth, its
action is more energetic, and its phenomena are
more apparent than in old age. Nevertheless,
bones ever remain bones, and arteries continue
arteries. In spite of the continual change of
the elements which compose an animal's body,
the form of its different organs is not altered.
Slight modifications may occur; but in the
animal, as in the vegetable, we observe a
permanence of form. The characteristic structure
remains intact.

The animal grows for a certain time, after
which its development is arrested. Every living
being has its appointed stature, which varies
only within restricted limits. It is subject to a
limit of size, like that observed in the vegetable.
Finally, the animal lives. It first grows, and
then ceases to grow, without, however, ceasing
to live. The duration of its existence is
intimately connected with the duration of its
development; the longer its growth has lasted,
the longer will its adult life last. Nature
destroys her own handiwork at a rate of slowness
corresponding to that which she employed in