This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Sinapi Pharm. Lond, Sinapi album Pharm. Edinb. Sinapi rapi folio C. B. Sinapis. nigra Linn. * (b). Mustard: an annual plant; with long rough leaves divided to the rib into irregular segments, of which the extreme one is largest; producing, at the tops of the branches tetrapetalous yellow flowers, followed, each, by a short, smooth, quadrangular pod, divided longitudinally by a membrane which projects at the ends, containing small, roundish, reddish-brown or dark-coloured seeds. It is a native of England, but commonly cultivated for medicinal and dietetic use.
(a) Hift. dyfenteriae biliofo-contagiofae, in Append, ad act. nat. curiof. vol. v.
* (b) The Sinapis alba is the Edinburgh species, which differs little from the black, or common, except in being less pungent and bitter. It should seem therefore to be less proper for external use, at least.
Mustard seed is one of the strongest of the pungent, stimulating, 'diuretic medicines that operate without exciting much heat. It is sometimes taken, unbruifed, to the quantity of a spoonful at a time; in paralytic, cachectic, and serous disbrders. In this manner of exhibition it generally opens the body; whereas the powder is apt to occasion vomiting, in which intention it is sometimes given diffused in warm water, of which repeated draughts must be drunk, to continue the effect. It is applied also, as an external stimulant, to benumbed or paralytic limbs; to parts affected with fixt rheumatic pains; and to the soles of the feet, in the low stage of acute diseases, for raising the pulse: in this intention, a mixture of equal parts of the powdered seeds and crumb of bread, with the addition sometimes, of a little bruised garlick, are made into a cataplasm with a sufficient quantity of vinegar.
Mustard seed yields upon expression a considerable quantity of oil, which is by some recommended externally against rheumatisms and palsies, though it has nothing of that quality by which the seeds themselves prove useful in those disorders; the oil being mild and infi-pid as that of olives, and the pungency of the seed remaining entire in the cake left after thexpression, expression. Nor is any considerable part of the pungent matter extracted by rectified spirit; the tincture, which is of a pale amber colour, having very little taste; and the extract, obtained by infpifTating it, being only bitterish and oily: the quantity of extract is about one six-teenth the weight of the seeds. The bruised seeds give out readily to water nearly the whole of their active matter: added to boiling milk, they curdle it, and communicate their pungency to the whey. Distilled with water, they yield a limpid essential oil, extremely pungent and penetrating both in smell and taste, and so ponderous as to fink in the aqueous fluid: the remaining decoction, thus diverted of the principle in which alone the acrimony of the mustard resides, leaves on being infpifTated a fweetift. mucilaginous extract.