473. Mentha piperita.—Peppermint. 473a. Oleum Menthae Piperitae U.S. 473b. Menthol.

The-dried leaves and tops of Men'tha piperita Linné.

DESCRIPTION.—Leaves petiolate, ovate, lanceolate, about 2 inches (50 mm.) long, acute, sharply serrate, glandular, nearly smooth; light or dark green flowers in terminal spikes, purplish; odor strong and characteristic; taste pungent and cooling. Statistics show that 300,000 pounds of peppermint are annually consumed by the world, and that more than 90 per cent. of this is grown within 25 miles of Kalamazoo, Mich. A few miles from Fenville, Mich., there are two famous mint farms, one section covers about 1400 acres, the other about 2100 acres. The former tract is known as the "Campania Farm" the other "Mentha Farm." A distilling plant is on the ground. An average yield of oil is about 20 pounds per acre. The "mint" industry is a specialty with peculiar features, combining farm and factory-agriculture in growing the plant, and the manufacture in separating the oil by distillation. There are about 80 "stills" in southwestern Michigan, and since there are 4000 acres of the plant under cultivation, one "still" is required for every 50 acres of peppermint.

Powder.—Microscopical elements of: See Part iv, Chap. I, B.

CONSTITUENTS.—Volatile oil, consisting of a terpene of complex composition (liquid) and menthol, C₁₀H₂₀O

ACTION AND USES.—Carminative and diffusive stimulant. Dose: 15 to 60 gr. (1 to 4 Gm.).

OFFICIAL PREPARATION.

Spiritus Menthae Piperitae (1 per cent.), Dose: 15 to 30 drops (1 to 2 Mils).

473a. Oleum Menthae Piperitae U.S.

A volatile oil distilled from peppermint. A colorless, or yellowish, or greenish-yellow liquid, turning darker and thicker by age and exposure to the air, having a strongly aromatic, pungent taste, followed by a sensation of cold when air is drawn into the mouth. Its composition is very complex, consisting of a number of terpenes, aldehydes, and acids: pinene, phellandrene, cineol, dipentene, limonene, menthone, and menthol, etc. In a freezing mixture the oil becomes cloudy and thick, and will separate crystals of menthol (473b). The oil yields not less than 5 per cent. of esters calculated as methyl acetate and not less than 50 per cent. of total menthol.

OFFICIAL PREPARATIONS.

Aqua Menthae Piperitae (0.2 per cent.). Dose: 4 fl. dr. (15 mils)

Spiritus Menthae Piperitae (10 per cent.), 15 to 30 drops (1 to 2 mils).

473b. Menthol.

A secondary alcohol from the official oil of peppermint (from Mentha piperita Smith), or from Japanese or Chinese oil of peppermint (from Mentha arvensis Linné, variety piperascens Holmes, and Mentha canadensis Linné, variety glabrata Holmes). Colorless, acicular or prismatic crystals, having a strong and pure odor of peppermint, and a warm, aromatic taste, followed by a sensation of cold when air is drawn into the mouth. It is slightly soluble in water, freely soluble in olive-oil, and very soluble in alcohol, ether, chloroform, and in petroleum benzin. When menthol is triturated with about an equal part by weight of camphor, thymol or hydrated chloral, the mixture becomes liquid.

Lubulinski recommends the use of a solution of menthol in liquid paraffine for acute coryza. Dose: 0.06 Gm. (1 gr.).

A Manual of Organic Materia Medica and Pharmacognosy, 1917, was written by Lucius E. Sayre, B.S. Ph. M.