166. Marrubium vulgare, Linn.—White Horehound.
Tribe IV. Stachydeae, Benth.
Stamens 4, ascending under the helmet (which is usually concave).
Sex. Syst. Didynamia, Gymnospermia.
History.—This is the plant which is called Πράσιον by Hippocrates, Theophrastus, and Dioscorides; [Lib. iii. cap. 119.] and Marrubium by Pliny. [Hist. Nat. lib. xx. cap. 89, ed. Valp.]
Botany. Gen. Char.—Calyx tubular, 5—10-nerved, equal; teeth 5—10, acute, somewhat spinous, nearly equal, erect, or often spreading at maturity. Corolla with an inclosed tube, which is naked inside, or somewhat annulated, and a 2-lipped limb; the upper lip erect, flattish or concave, entire or shortly bifid; the lower lip trifid, spreading, the middle lobe the broadest, often emarginate. Stamens inclosed within the tube of the corolla; anthers with 2 straggling, somewhat confluent cells, all nearly alike. Style bifid at the apex, with short obtuse lobes. Nucules obtuse, not truncate at the apex (Bentham).
Sp. Char.—Branches white-woolly. Leaves ovate or rounded, softly villous, greenish or white-woolly beneath, crenate. Whorls many-flowered. Calyx villose, woolly, with 10 subulate, recurved-spreading or woolly teeth. Corolla with an oblong helmet, bifid at the point (Bentham). Flowers white.
Hab.—Dry,waste grounds. Indigenous. Grows in most parts of Europe; also in Asia and America. Flowers in July.
Properties.—The whole herb (herba marrubii) is used in medicine. It has an aromatic odour, and a bitter taste. Sesquichloride of iron communicates an olive-green tint (tannate of iron) to the cold watery infusion.
Composition.—Its bitterness depends on extractive; its aromatic properties on volatile oil. Besides these principles it contains resin, tannic acid, bitter matter, and woody fibre.
Physiological Effects.—Horehound is tonic, mildly stimulant, and, in large doses, laxative. Taken in the form of infusion, it promotes the secretions of the skin and kidneys. It was formerly supposed to possess emmenagogue properties.
Uses.—It is rarely employed by medical practitioners. As a domestic remedy it is used in chronic pulmonary complaints, especially catarrh. It was formerly given in uterine and hepatic affections.
Administration.—Horehound tea (prepared by infusing an ounce of the herb in a pint of boiling water) is taken in the dose of a wineglassful. Syrup of horehound (prepared with the infusion and sugar) is a popular remedy, and is kept in the shops. Candied horehound ought to be made of the same ingredients.
Ballota Nigra, Linn., or Stinking Black Horehound, possesses similar properties to the Marrubium vulgare.