analysis of which vegetables are susceptible;
first, that which separates them into their immediate materials, such as
sap, resin, mucilage, &c.; secondly, that which decomposes them into
their primitive elements, as carbon, hydrogen, and oxygen.

EMILY.

Is there not a third kind of analysis of plants, which consists in
separating their various parts, as the stem, the leaves, and the several
organs of the flower?

MRS. B.

That, my dear, is rather the department of the botanist; we shall
consider these different parts of plants only, as the organs by which
the various secretions or separations are performed; but we must first
examine the nature of these secretions.

The _sap_ is the principal material of vegetables, since it contains the
ingredients that nourish every part of the plant. The basis of this
juice, which the roots suck up from the soil, is water; this holds in
solution the various other ingredients required by the several parts of
the plant, which are gradually secreted from the sap by the different
organs appropriated to that purpose, as it passes them in circulating
through the plant.

_Mucus_, or _mucilage_, is a vegetable substance, which, like all the
others, is secreted from the sap; when in excess, it exudes from trees
in the form of gum.

CAROLINE.

Is that the gum so frequently used instead of paste or glue?

MRS. B.

It is; almost all fruit-trees yield some sort of gum, but that most
commonly used in the arts is obtained from a species of acacia-tree in
Arabia, and is called _gum arabic_; it forms the chief nourishment of
the natives of those parts, who obtain it in great quantities from
incisions which they make in the trees.

CAROLINE.

I did not know that gum was eatable.

MRS. B.

There is an account of a whole ship's company being saved from starving
by feeding on the cargo, which was gum senegal. I should not, however,
imagine, that it would be either a pleasant or a particularly eligible
diet to those who have not, from their birth, been accustomed to it. It
is, however, frequently taken medicinally, and considered as very
nourishing. Several kinds of vegetable acids may be obtained, by
particular processes, from gum or mucilage, the principal of which is
called the _mucous acid_.

_Sugar_ is not found in its simple state in plants, but is always mixed
with gum, sap, or other ingredients; this saccharine matter is to be met
with in every vegetable, but abounds mos