399. Ammoniacum.—Gum Ammoniac.
399. AMMONIACUM.—GUM AMMONIAC. A gum-resin exuding from Dore'ma ammoni'acum Don. Off. U.S.P., 1890. Roundish tears varying in size from 1.5 to 12 mm. (1/16 to ½ in.) in diameter, externally yellow or pale yellowish-brown. When warm it is of the consistence of wax, but it becomes brittle when cold, breaking with a milk-white, waxy fracture, translucent at the edges; odor balsamic, stronger on heating; taste acrid, bitter, and nauseous. Lump ammoniac is an inferior quality in which the tears are agglutinated. Cake ammoniac is a very impure, dark-colored, resinous mass exuding from the roots; imbedded in it are a few tears and much vegetable and earthy trash; it is not used internally. Constituents.—Volatile oil, gum resembling acacia, resin (about 70 per cent. composed of two, one acrid resin and one indifferent resin); it yields no umbelliferone. By fusing with KOH, yields protocatechuic acid and resorcin, C6H6O2, Among the derivatives of the acid resin are salicylic acid, ammoresinotannol, etc. Similar to asafoetida—stimulating expectorant, antispasmodic and laxative-but less powerful. Dose: 10 to 30 gr. (0. 6 to 2 Gm.).
- Emulsum Ammoniaci (4 per cent.), U.S.P. 1890 Dose: ½ to 1 fl. oz. (1.5 to 30 mils).
- Emplastrum Ammomaci cum Hydrargyro (72 per cent., with mercury, oleate of mercury, dilute acetic acid, and lead plaster), U.S.P. 1890.