Mustard, or Sinapis, L. a genus of plants, comprising nineteen species : three of which are natives of Britain : namely,

1. The arvensis. See Charlock.

2. The alba, or White Mustard, which grows in corn-fields, and on road-sides; it flowers in the month of August. - This species, when cultivated, thrives best in a soil that is naturally heavy, but which has been reduced to a fine mould, by tillage : it is propagated by sowing one bushel of the seed per acre, in the month of March ; it should be frequently hoed ; and, when the plants arrive at a proper size for transplantation, they may be set out, ten inches apart. Mustard may be sown on the same land, for three successive years; and it always leaves the soil in sufficient licient tilth for the reception of any other crop. Its leaves afford a grateful food to sheep, and other cattle : the seed yields from every cwt. 33 or 36lbs. of a sweet, mild oil.—Bees are remarkably attached to the flowers.—'This plant is likewise raised by gardeners in the winter, and early in the spring, with a view to supply the table with salad.

3. The nigra, or Common Mus-tard, growing in corn-fields, on ditch-banks, and road-sides ; flow-ering in the month of June.—The sauce, called mustard, and in daily use at our tables, is prepared from the seeds of this species, obtained by culture, and reduced to powder. They likewise afford a considerable quantity of expressed oil, which partakes but little of the acrimony of the plant.—When unbruised, they impart a very weak flavour to boiling water; but, in a pulverized state, they coagulate milk, and strongly impregnate both fluids.— If a watery infusion be taken in a considerable quantity, it operates as an emetic; but, in the proportion of a table-spoonful or two, it is a gentle laxative; in this form, it has proved of service in cases of asthma, chronic rheumatism, and palsy.—Cataplasms, prepared with crumb of bread, vinegar, and pulverized mustard-seed, are excellent stimulants, when applied to benumbed or paralytic limbs: to parts affected with fixed rheumatic pains, and to the soles of the feet, in fevers that require such treatment.—In short, mustard a6ts powerfully upon the nervous system, without exciting a high degree of heal: by its acrimony and pungency, it stimulates the solids, and attenuates viscid juices; so that it is. deservedly recommended for exciting appetite, assisting di-gestion, and promoting the fluid secretions, being greatly preferable to the generality of acrid plants of the antiscorbutic class.

In 1798, a patent was granted to Mr. Robert Johnston, for his contrivance of a medicine, which he calls Improved Essence of Mustard. The particulars of this patent are inserted in the 9th vol. of the Repertory of Arts, etc.