Sinapis. Mustard. The seed of Sinapis nigra and Sinapis alba, or Black and White Mustard; Lin. Syst., Tetradynamia siliquosa: plants common in Europe.

Description. Black mustard seeds are very small, round, wrinkled, and brownish-black on the surface, yellow within; white mustard seeds are larger, and yellow on the surface. The seeds reduced to powder are the officinal part.

Prop. & Comp. When crushed, both seeds yield the flour of mustard; the best is made from the mixed seeds; when dry, it has little or no odour, but an acrid, bitterish, oily, pungent taste, and gives off, when moist, a peculiar pungent smell, very irritating to the eyes and nostrils. Both seeds contain a fixed oil, from 25 to 35 per cent. Black mustard contains no volatile oil ready formed, but a principle named myronic acid, united with potash, containing about 1/5 per cent.; the myronate of potash has the composition (KO, C20 H19 No18) and by the action of an albuminous matter also contained in the seed, and termed myrosine, breaks up, in the presence of water, into the oil of mustard, sugar, and probably bisulphite of potash. The volatile oil of mustard is of a slight yellow colour; sp. gr. about 1.03; very pungent and acrid; has the composition (C8 H5 Ns2) or C6 H3, C2 Ns2), Sulphocyanide of Allyle. White mustard does not yield the volatile oil, but contains a crystallisable compound, sulphosinapisin, which gives rise to an acrid but not volatile principle, containing sulphur. This compound has been supposed to be the hydrosulphocyanide of a peculiar alkaloid sinapine (C32 H23 No10.) The fixed oil of mustard contains erucic acid (HO, C44 H41 O3). A decoction of flour of mustard, when cooled, should not be made* blue by tincture of iodine, indicating the absence of starch.

Off. Prep. Cataplasma Sinapis. Mustard Cataplasm. [Not officinal in U. S. P.] (Boiling water, ten fluid ounces; powdered linseed, powdered mustard, of each two ounces and a half. By degrees add the powders, first well mixed, to the water; keep stirring that a cataplasm may be formed.) Too hot water, or alcohol, or vinegar are apt to injure the production of the volatile oil.

Therapeutics. Mustard seeds and flour act as powerful stimulants. Internally, in large doses, mustard causes speedy vomiting (useful in narcotic poisoning); in smaller doses, as a condiment, it assists digestion. The entire seed was formerly used, and now and then caused ill effects, from accumulating in the intestines. Externally, in the form of cataplasma sinapis, it is a powerful rubefacient, useful in slight inflammations, head affections, neuralgic and other pains and spasms.

Dose. As an emetic, from one teaspoonful to a tablespoonful mixed with a little water.

Adulteration. Flour of mustard is extensively mixed with common flour, pepper, chilies, turmeric, etc.

Armoracia. Horseradish. The recent root of Cochlearia Armo-racia [not officinal in U. S. P.]; Lin. Syst., Tetradynamia sili-culosa: common throughout Europe, cultivated in Britain.

Description. A long, white, tap-shaped root, familiar to all.

Prop. & Comp. When scraped, it emits a very pungent odour, and has an acrid taste, depending on a volatile oil (C8 H5 Ns2) identical with oil of mustard; probably the oil is formed as in the black mustard seed.

Off. Prep. Spiritus Armoraciae Compositus. Compound Spirit of Horseradish. (Horseradish sliced, dried orange peel, each twenty ounces; bruised nutmeg, half an ounce; proof spirit, a gallon; water, 2 pints. Mix them; let a gallon distil with a moderate heat.)

Therapeutics. The same as mustard; seldom employed in the fresh state except as a condiment. The officinal preparation is used in atonic dyspepsia; also as a sudorific in chronic rheumatism, etc. As a syrup it has been slowly swallowed in hoarseness, an infusion is also occasionally prescribed.

Dose. Of spiritus armoraciae c, 1 fl. drm. to 3 fl. drm.