influence of a cell of one kind over a cell of
another kind—of the sperm-cell over the
germ cell; the latter process, consisting in
the multiplication of the original cell by
division—a realisation of the old paradox—
occurs when we break off a slip from a tree,
and from this develope a perfect plant. Here,
growth takes place solely in virtue of the
characteristic power which the individual cell
possesses of forming new cells in its interior,
which grow and arrange themselves
conformably to the vehicle from which they
originate. The gardener, in grafting and
budding, avails himself practically of this
attribute of the cell, otherwise essential as
the means of growth in every plant. We
especially wish to distinguish this function
from the propagation; it is of the highest
importance to the student that he should
perceive the radical difference between the two
processes: and we insist on it the more, here,
in the hope that some readers of these pages
may be led to pursue the subject, and knowing
that some of the greatest physiologists,
while acknowledging the vast importance
of the distinction, have not so stated it
as to arrest the student's attention.
Continuation of the individual, can occur by the
action of one cell only, which exhausts its
vitality in developing other cells, as it were
offshoots of itself and supplementary of its
vital power. For reproduction the confluence
of two cells is essential, the one of which
acts upon the other so as to give rise to new
and separate individual existence—in itself
whole—entire and distinct. It is in the first
instance by establishing the universal agency
of cells in the performance of these great
natural functions, and afterwards by
distinguishing between the modes in which they
acted, and the differing laws by which they
were regulated, that physiologists have
succeeded in throwing light upon the sacred
mysteries of nature. For, the application of
these principles is far from being confined
to the vegetable world; the egg of the chick
obeys the same laws as the seed of the plant,
and thus a sublime harmony is established
throughout the organic world, such as was
never before dreamed of in our philosophy.

Marvellously beautiful are the provisions
by which the seed is fitted to play its part in
the history of the world, where it appears as
at once the parent and sustainer of life, the
author of vegetable, the support of animal
life. So perfect, though withal so simple, is
this provision, that seeds have been known to
retain their vitality upwards of three thousand
years, and, when planted in the earth, to
germinate and bring forth. The process of
germination itself, is attended with special
phenomena of the most impressive interest.
The cells of the embryo plant require all their
energy for the rapid development of its
tissues by the formation of new cells; if they
were diverted from their active employment
in promoting growth in bulk, in order to
separate and prepare their own food, it would
be at the expense of the rapid development
of the plant, which is the great object in view.
A most beautiful provision is therefore made
for the supply of food to the embryo. The
seed is supplied with a coating of albumen
and starch; part of this, resolves itself by a
process of decomposition into a nutritive fluid
which offers to the embryo cells all the
materials of growth already elaborated and
prepared for use; while a part, absorbing
oxygen, which combines with its carbon,
creates an artificial atmosphere of carbonic
acid gas, the natural food of the plant, thus
at once accustoming the embryo to look
forward to an independent life, and, as it
were, emancipate itself from a future necessity
for foreign help. The interest attaching to
this peculiar function of the albumen of the
seed will hardly be diminished by the
reflection that it is this also which gives to the
seed its value to man as an article of food,
and places all kinds of grain so high in the
dietetic scale. Nowhere, perhaps, is the
aphorism of Malpighi more applicable: Tota
natura existit in minimis—nature's highest
powers are seen in pigmy forms.

The fertility of resource which these powers
can display, appears almost exhaustless; they
overcome all material difficulties and are
baffled by no physical obstacle. In the
process of reproduction, not only is it
necessary that the pollen-cells and the germ-
cells be relieved simultaneously, so that, at
the moment of effusion of the one, the other
are ready to receive them; but provision
must be made for those cases in which the
relative position of stamen and germen is
such as to apparently preclude the possibility
of their being brought into contact. In many
flowers, the stamens are placed at a distance
around the germen, and here they may be
seen to contract their circle of distance, curve
over, and shed their golden shower of pollen-
cells. In others, the lofty pistil towers above
the stamens, and then the flower gracefully
droops its head, so that the pollen, in falling,
will reach its destination, or the pistil itself
gently bends until it touches the stamen, and
forthwith returns to its former position,
instinct with animal life. But, sometimes, as
in the orchids and other families of plants, the
complicated structure of the organs and their
irregular position seem to defy the efforts of
vegetable nature and set her powers at nought.
Foreign forces then come to her aid, and,
while revolving in undisturbed vicissitude in
the performance of their own natural duties,
exert so powerful and essential an influence
over the development of the plant world, that
it is difficult to believe that this is not their
peculiar task. For, if it be land-plants that
require this foreign aid, the breeze will carry
far and wide the showers of pollen-cells, and
scatter, at least, a part of them over the
productive plant; if it be water-plants that
require this foreign aid, then the waves wash