MUSTARD, Ora, ma The seeds both of the black and the white mustard yield by expression a large quantity of a bland fixed oil, but they do not contain any essential or volatile oil ready formed. It is only the black mustard which by distillation yields the compound usually known as the oil or essence of mustard, and which if in reality sulpho cyanide of allyl (see- WO with a little brown resinous matter, from which it may be freed by simple redistillation.
When first obtained, it is a colorless fluid, which gradually becomes yellowish. It has a painfully pungent odor and acrid taste; and when applied to the skin, it speedily raises a blister. It is soluble in all proportions in alcohol, but dissolves very sparingly in water. In the article already referred to, it has been shown that this oil and oil of garlic are naturally convertible into one another; in combination with ammonia it forms a compound which is termed thiosinnamine. and which combines directly with acids like a
true organic base. Its mode of formation is explained by the equation: Oil of Mustard. Ammonia. Thiosinnamine. 0e116,C2NS2 = By digesting oil of mustard with alkalies, or with hydrated oxide of lead, we also obtain a feeble base termed sinapoline, whose formula is The oil is formed in lunch the same way as the volatile oil of almonds (q.v.) The black mustard contains the potash sall'of a compound termed Byronic acid, and a pecu liar coagulable nitrogenous ferment. which. when the crushed seed is moistened with water, act upon each other, and develop the oil. It is the gradual formation of this oil, when powdered mustard and warm water are mixed, that occasions the special action of the common mustard poultice. The pungency of mustard as a condiment, of horse-rad ish, etc., is mainly due to the presence of this oil.