Ammoniacum. Gum Ammoniac.
Nat. Ord. — Apiaceae. Sex. Syst. Pentandria Digynia.
The Concrete Juice of Dorema Ammoniacum.
Description. — The Dorema Ammoniacum has a large, perennial root, with stems rising from seven to ten feet high, about four inches in circumference at the base, clothed with a glandular down, smooth, glaucous, resembling Opoponax. The leaves are large, petiolate, somewhat two-pinnate. Pinnae in three pairs, each pair somewhat remote. Leaflets inciso-pinnatifid, with oblong, mucronulate, entire, or slightly-lobed segments, coriaceous. Petiole downy, very large, and sheathing at the base. Umbels proliferous, racemose; partial umbels globose, on short stalks, often arranged in a spiked manner. General and partial involucre wanting. Flowers sessile, immersed in wool. Petals white, ovate, reflexed at the point. Margin of calyx with five minute, acute, membranous teeth. Disk large, fleshy, cup-shaped. Stamens and styles yellow, the latter complanate, recurved at apex. Stigmas truncate. Ovary very woolly. Fruit elliptical, compressed, with a broad flat edge; mericarps with three distinct, filiform, primary, dorsal ridges, and alternating with them are four obtuse, secondary ridges. Vittae, one beneath each secondary ridge, one beneath each of the broad marginal primary ridges, and two on each side of the suture of the commissure, the external ones being very minute. The above description is gathered from those given by Don, Fontannier, and others.
History. — For a long time a knowledge of the plant which furnishes the Gum Ammoniac was a matter of doubt and uncertainty, but from specimens obtained in Persia, by Colonel Wright, and examined by Dr. David Don, it was ascertained to belong to a genus, Dorema, and not to the Ferula, as was formerly supposed, although somewhat allied to it. The Dorema Ammoniacum is an umbelliferous plant, growing spontaneously in various Persian provinces, in dry plains and gravelly soils. In the month of May, or in the early part of summer, it abounds in a milky juice, which flows out upon the slightest puncture. M. Fontannier states that it exudes spontaneously, and that the harvest is about the middle of June ; but Captain Hart says that when the plant is mature, it is pierced in all directions by an insect of the beetle kind ; the juice exudes through the punctures thus made, hardens upon the surface, and when dry is collected by the natives. It is still supposed, however, to be sometimes furnished by other and dissimilar plants of Asiatic as well as African growth.
Gum Ammoniac is not a pure gum, but a gum-resin ; it comes to us in tears, or in aggregate masses, and is frequently mixed with foreign matters. The tears are the preferable parts to use ; the purest are irregular in shape, more or less globular, opake, yellowish externally, whitish internally, compact, homogeneous, brittle when cold, and breaking with a conchoidal shining fracture. The masses are darker, and of less uniform structure, and appear when broken, to be composed of numerous tears imbedded in a grayish or brownish substance. Ammoniac has a peculiar smell, which is stronger in the masses than in the tears ; the taste is bitter, slightly sweetish, and somewhat acrid. Its specific gravity is 1.207. It softens by heat, and becomes adhesive, but does not melt ; and when burned, it swells up, with a white flame, and emits a smoke of a strong, resinous, slightly alliaceous odor. It forms an opake milky emulsion when triturated with water, but which becomes clear upon standing. It is partly soluble in alcohol, ether, vinegar, and alkaline solutions ; the alcoholic solution is clear, but becomes milky on the addition of water.
Properties and Uses. — Stimulant and expectorant, and in large doses cathartic. Used in chronic catarrh, asthma, cough, and chronic pulmonary affections, where from debility of the vessels there is too large a secretion from the bronchial mucous membrane, or where expectoration is deficient. It has likewise been advised in chronic amenorrhea, especially when attended by hysterical or chlorotic conditions of the system. It is unsuited to inflammatory affections. Dose, ten to thirty grains in pill or emulsion. Externally, used in the form of plaster, as a discutient or resolvent in scrofulous tumors, tumors of the joints, indolent tumors, etc.
Gum Ammoniac enters into a cement for mending glass, china, etc., and which is useful to druggists, physicians, chemists, and others ; it is called Armenian Cement, and Diamond Cement, and on account of its utility we give its mode of preparation. Take of isinglass two drachms, sprinkle it with water, and allow it to stand until softened, then add as much proof spirit as will leather more than cover it, and dissolve it with a moderate heat. Take of gum mastic one drachm, and dissolve it in two or three drachms of rectified spirit. Mix these -two solutions, and stir in one drachm of gum ammoniac, which has been previously reduced to fine powder, and rubbed down with a little water. If necessary, evaporate in a water-bath to about the consistence of thick molasses, and keep it in a bottle. When required for use place the bottle in warm water, and allow the cement to soften, then apply it with a stick, or a small hard brush to the china or glass previously warmed. Compress the pieces firmly together until cold, taking care to make the contact perfect, and using a very thin layer of cement. When properly applied the cement is almost, if not quite, as strong as the china itself, unless exposed to the combined action of heat and moisture.