294. Myrrha.—Myrrh.
A gum-resin obtained from one or more species of Commiph'ora myrrha Engler and other species.
BOTANICAL CHARACTERISTICS.—A shrub forming the chief underwood of the Arabian and African forests along the shores of the Red Sea. Squamose, spinescent branches, with pale, ash-gray, odorous bark; leaves ternate; flowers solitary, greenish; fruit drupaceous, with the persistent calyx attached.
SOURCE.—Myrrh is now imported from the East Indies, where it is brought from Arabia and the northeastern coast of Africa. It is usually imported in chests containing from one hundred to two hundred pounds. The terms Turkish and Indian myrrh are now obsolete. Up to recent times most of the myrrh came from India but now it chiefly comes direct from Aden.
DESCRIPTION OF DRUG.—Irregular masses of agglutinated tears, varying from small grains up to pieces about the size of an egg, or sometimes much larger; of a reddish-yellow to a reddish-brown color, dusty, opaque, waxy, and unctuous. Freshly broken, the shining surface often shows characteristic white marks or streaks. Odor pleasant, balsamic; taste bitter, aromatic. This description applies to the best Turkey-official myrrh. The India variety comes in darker pieces, more opaque, less odorous, and abounding in impurities. Bdellium and other gummy or resinous substances are of ten mixed with it. False myrrh is the name sometimes given to these other gummy and resinous substances. As it is difficult to detect adulteration when it is in the powdered form, it is best purchased in mass. The best variety yields a brownish-yellow tincture, which acquires a purple tint upon the addition of nitric acid. A tincture which does not show this color reaction betrays an impure article, which should be rejected.
Powder.—Microscopical elements of: See Part iv, Chap. I, B.
CONSTITUENTS.—A volatile oil, myrrhol (3 to 4 per cent.); a bitter principle; a resin, 35 per cent., and gum, 60 per cent., forming with water a yellowish or brownish emulsion, which deposits a sediment upon standing. Recent investigations of Tschirch and others, have cleared up many obscure points regarding the chemistry of the resins in such drugs as myrrh. An excellent classification of the resins is found in a volume entitled "Pharmacopedia," by White and Humphrey, London (PP. 400, 403) and in Allen's "Commercial Organic Analysis," (pp. 1-103, vol. iv, 4th edition). Myrrh of good quality should contain not more than 70 per cent. of matter insoluble in alcohol. Ash, not more than 8.5 per cent.
ACTION AND USES.—A stomachic, carminative, and emmenagogue. Used mostly in mouth-washes. Dose: 2.5 to 15 gr. (0.15 to 1 Gm.), in pills and emulsion.
OFFICIAL PREPARATIONS.
- Tinctura Myrrhae (20 per cent.), Dose: 10 to 60 drops (0.6 to 4 mils).
- Pilulae Rhei Compositae.
