residue, or oil-cake left after extraction, has
been tried to fatten cattle with; but the prussic
acid contained in it renders caution necessary
regarding the quantity given. Cows have been
poisoned by it. It may not be amiss to note
here, that in case of accident from an over-dose
of bitter almonds, laurel leaf, or other form of
prussic acid, a weak solution of sulphate of iron
is an antidote.

Among the curious names of old sorts of
plums, we find the Jerusalem plum, or bull's
eye, very large indeed, brownish purple, and
more square than round; the bull's heart, or
Saint Loo plum, one of the very largest, with
yellow flesh and red skin; the pigeon's heart,
black, large, and excellent, late in the season;
the transparent plum, large, light-coloured, and
long: so called because, when held up to the
sun, the kernel is clearly visible; the cock's
kidney, small, late, kidney-shaped, and light
yellow spotted with red. Aldovrandi, who was
acquainted with everything on earth, mentions
not only an asses' paradise, but also asses' plums
(Pruna asinina), formerly so styled on account
of their cheapness. They are later and larger
than, but of the same colour as, harvest plums
(Pruna hordearia).

Prunum is Latin for plum fruit, prunus
(substantive feminine) for the plum tree, both
being derived from ??????, the name by which
Theophrastus mentions it. Prunus is an
important genus in the class Icosandria Monogynia
of the Linnæan system. It belongs to the tribe
of almond-like plants, which are themselves
included in the Rosaceae, or rose-like plants. It
is composed of trees and shrubs peculiar for the
most part to the temperate and moderately
warm regions of the northern hemisphere: a few
being also found in America, and in tropical
Asia. Their leaves are simple, alternate, entire,
or indented with teeth like a saw. Their
flowers generally appear very early, while the
leaves are still but slightly or scarcely
developed. To the blossom succeeds a fleshy drupe,
whose stone, not wrinkled (distinguishing it
from a peach), contains a single seed (sometimes
twins).

Linnæus's genus plum, therefore, comprises
the true plums, the apricots, and the cherries,
of which Tournefort made three distinct
genera. He even subdivided the latter into
two; the cherries proper, and the laurel cherries.
Jussieu followed Tournefort's example, which
is sanctioned by modern botanists, less,
however, on account of the importance of the
distinctive characters displayed by the three
groups, than to make scientific language accord
with popular phraseology. The million are
indifferent about botanical niceties and floral
anatomy; but they know an apricot from a
plum, and from a cherry, at a glance. An
apricot has a downy skin; a plum has a smooth
skin powdered with a secretion called "the
bloom," which is removed by a very slight
touch, and is sometimes imitated by arrowroot.
A cherry has a smooth shining skin, like
a maiden's lip, and grows on a longer stalk than
either of the former. There is no cherry with
the down of an apricot, or the bloom of a
plum; and vice versa. The plum differs from
the others in having fruit green when ripe.
There is no green ripe apricot or cherry; but
there is it— makes one's mouth water to name
it— a greengage; and also a bullace, which acts
on the imagination like an acid astringent.

A plum, then, is a drupe, mostly egg-shaped
or oblong, fleshy, quite smooth, covered with a
sort of bluish dust, containing a flattened stone
sharp at both extremities and slightly furrowed
at the edges. The young leaves of the tree are
rolled or twisted when they first appear. The
flowers, solitary or in couples, proceed from
buds special to themselves, at the same time
with, or before, the leaves. The wild plum of
Europe, Prunus spinosa, familiar as the blackthorn
or sloe-bush, has numerous thorny branches,
which ramify at almost right angles. Its white
blossoms appear so early in spring, that Cobbett
happily styled the stormy time of their appearance
"the blackthorn winter." Its small, blue-
black, almost globular fruit, is too astringent to
be eaten, although early frosts slightly soften its
flavour and develop a sugary principle. In
that condition, it is certainly employed in
France (we say nothing of England) to flavour
and colour wines of inferior quality. The poor
also make a wretched beverage by fermenting
crushed sloes in a certain quantity of water.
The sloe likewise furnishes a very strong vinegar;
frosted sloes, prepared like tamarinds, are
not a bad substitute for that Indian preserve.
The bark of the blackthorn is bitter, astringent,
antifebrile, and is, in fact, the most powerful
indigenous febrifuge, coming nearer to Peruvian
bark than any other native succedaneum. For
this purpose, it should be peeled in spring from
branches of four or five years' growth, and dried
slowly to be kept for use. It contains sufficient
tannin to serve for leather-making and for dyeing.
An infusion of sloe-leaves gives a humble
imitation of tea; the drinker's fancy is at liberty
to decide whether the bohea or the gunpowder
flavour be predominant. During the high price
of the China article, British foliage was liberally
mixed with it. The wood of the blackthorn is
hard and durable. Capital walking-sticks are
made from the vigorous suckers which the bush
throws up in considerable abundance. A blackthorn
hedge is efficient, and lasts long with
proper care, although it be less rapid in growth,
and less pleasing both in verdure and in
blossom, than one of white thorn— i.e. hawthorn.
Who would guess that so many uses could be
drawn from the stunted sloe-bush on which we
look scornfully as it struggles for life on the
skirts of a common?

The garden plum, Prunus domestica, attains
the stature of a small tree. Its boughs are
spreading, without thorns, and covered with a
greyish skin, whilst the older branches are
brownish. Its white flowers give birth to a
drooping fruit, of sweet and slightly perfumed
savour, and of very diverse form and size.
While cherries grow on stalks longer than themselves,