A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS. iiO
GLTJCOSIDES.
Nearly all plants contain peculiar compounds, which have the property
in common to be resolved into a sugar, and other compounds, by
the action of acids, alkalis, or ferments. Some of these glucosides
occur also in the animal kingdom.
The chemical character of these bodies shows that they are compound
ethers of sugar or of bodies nearly related to them, such aa
gum, starch, &c.
The number of glucosides known is very large, and most of them
yield products of decomposition belonging to tlie aromatic group.
We can describe here only those of more importance.
Myronic Acid C10H,9NSjO10.—The potassium-salt of this acid exists
in the seed of the black mustard, and is obtained by boiling the
crushed seed3 with alcohol, and exhausting the residue with water.
It crystallizes in silky needles; on boiling it with baryta-water, or by
the action of a ferment called myrosin, which is contained in the
seed, it splits up into mustard-oil, glucose, and acid potassium sulphate
:—
CJ0H18KNSaOw = C4H6NS + Cfi.fi, + HKSO,
The free myronic acid, which has been prepared by decomposing
the potassium-salt with tartaric acid, is a very unstable compound.
When silver nitrate is added to a solution of the potassiuin-salt, a
white precipitate consisting of C4H6NAg»S2O4 is formed, and glucose
remains in solution. Hydrogen sulphide decomposes this salt into
Rulphnr, silver sulphide, sulphuric acid, and crotonitrile :•—
C1H6NAg8S8O4 + HaS = S + AgaS +
GLUCOSIDES OF TIIE AfiOMATIC GROUP.
Amygdalin (LJH^NOJJ occurs in the kernels of cherries, plums,
apricots, &