s in its own volume of alcohol of this strength.

The oil contains eugenol, myrcene, chavicol, methyl eugenol, methyl
chavicol, phellandrene, and citral.

_Bergamot oil_, obtained by expression from the fresh peel of the fruit
of Citrus Bergamia, and used very largely for the perfuming of toilet
soaps. Specific gravity at 15 deg. C., 0.880-0.886; optical rotation, +10 deg.
to +20 deg.; esters, calculated as linalyl acetate, 35-40 per cent., and
occasionally as high as 42-43 per cent.; frequently soluble in 1.5 parts
of 80 per cent. alcohol, or failing that, should dissolve in one volume
of 82.5 or 85 per cent. alcohol. When evaporated on the water-bath the
oil should not leave more than 5-6 per cent. residue.

Among the constituents of this oil are: linalyl acetate, limonene,
dipentene, linalol, and bergaptene.

_Bitter Almond Oil._--The volatile oil obtained from the fruit of
_Amygdalus communis_. Specific gravity at 15 deg. C., 1.045-1.06; optically
inactive; refractive index at 20 deg. C., 1.544-1.545; boiling point,
176-177 deg. C.; soluble in 1 or 1.5 volumes of 70 per cent. alcohol.

The oil consists almost entirely of benzaldehyde which may be estimated
by absorption with a hot saturated solution of sodium bisulphite. The
chief impurity is prussic acid, which is not always completely removed.
This may be readily detected by adding to a small quantity of the oil
two or three drops of caustic soda solution, and a few drops of ferrous
sulphate solution containing ferric salt. After thoroughly shaking,
acidulate with dilute hydrochloric acid, when a blue coloration will be
produced if prussic acid is present.

The natural oil may frequently be differentiated from artificial
benzaldehyde by the presence of chlorine in the latter. As there is now
on the market, however, artificial oil free from chlorine, it is no
longer possible, by chemical means, to distinguish with certainty
between the natural and the artificial product. To test for chlorine in
a sample, a small coil of filter paper, loosely rolled, is saturated
with the oil, and burnt in a small porcelain dish, covered with an
inverted beaker, the inside of which is moistened with distilled water.
When the paper is burnt, the beaker is rinsed with water, filtered, and
the filtrate tested for chloride with silver nitrate solution.

_Canada snake root oil_, from the root of Asarum canadense. Specific
gravity at 15 deg. C., 0.940-0.962; optical rotation, slight