Alumen. D. Alum.
Qualities. Form, octohedral crystals, whose sides are equilateral triangles; they are slightly efflorescent. Taste, sweet, rough, and acidulous. Chemical Composition. It is a triple, or sometimes a quadruple salt, with excess of acid, consisting of sulphuric acid and alumina, with potass, or ammonia, or frequently both of them; the nature of the alkali however does not in the least appear to affect the properties of alum, although it produces a crystallographic modification; for where potass is present the summit of the crystal will exhibit a truncation. Dr. Ure has lately produced alum with soda, and the combination differs from common alum only in its greater degree of solubility, a property which at once recommends it to the attention of the pharmaceutist and physician. Solubility. A fluid-ounce of cold water dissolves 30 grains, but if boiling four drachms; it is insoluble in alcohol. Incompatible Substances. Alkalies and alkaline salts, after neutralizing the excess of acid, precipitate the alumine. It is also decomposed by carbonate and muriate of ammonia, carbonate of magnesia, and tartrate of potass, by lime-water, acetate of lead, and the salts of mercury, as well as by many vegetable and animal substances, especially galls and kino. It is on this account very injudicious to combine alum with any vegetable astringent with a view to encrease its virtues; thus the “Pulvis Sulphatis Aluminæ compositus” of the Edinburgh college, is less powerful than any of the ingredients of which it is composed; and the addition of alum to the decoction of bark, undoubtedly diminishes its efficacy as an astringent injection. Medicinal Uses. Alum is internally a powerful astringent, in hæmorrhages and inordinate fluxes, and is externally useful for repellent and astringent lotions, gargles, and collyria. Dioscorides and Hippocrates praised its effects as a lotion in various kinds of ulcers, and particularly in sores of the mouth, and in spongy, swelled gums. Van-Helmont was the first person who employed alum in uterine hemorrhage, and the success of the practice very considerably enhanced his reputation. Boerhaave’s astringent powder for the ague consisted of Alum and Nutmeg with the addition of Armenian bole. Dose, gr. x. In large doses it is liable to excite nausea, and to act upon the bowels. Nutmeg or some aromatic should therefore be joined with it. Forms of Exhibition. In solution, or in substance made into pills with extract; (Form: 53, 56,) it is sometimes given with advantage in the form of whey (Alum-whey—Serum Aluminosum) made by boiling ʒij with a pint of milk, and then straining, the dose of which is a wine glass full; (Form; 54.) By briskly agitating a drachm of alum with the white of an egg, a coagulum is formed, (Alum curd of Riverius; Albumen. Aluminosum) which is serviceable in some species of ophthalmia, when applied between two pieces of thin linen rag.[[365]] As alum is not decomposed by sulphate of lime, hard water may be safely used for its solution. It has the effect of retarding, and in some instances of preventing, the acetous fermentation in vegetables; thus when added to common paste it prevents its becoming sour; animal substances, as glue, are preserved by it in a similar manner. It has also the property of clearing turbid water, wine, and spirituous liquors, for which purpose it is extensively employed. Officinal Preparations. Liquor Alum: co. L. Pulv: Alum: co. E.
Alumen Exsiccatum, L. Ustum. D. Dried Alum. By the action of heat alum undergoes watery fusion, yields its water of crystallization, and loses more than one third of its weight; if the heat be too intense, or long continued, it is deprived of a great part of its acid. It has been recommended in doses of a scruple, in cholic, when it has been said to operate gently upon the bowels, and to relieve the pain: I have myself experienced this good effect when the cholic has been produced by the action of lead: Dr. Grashuis, a Dutch Physician, first recommended its use in Cholica Pictonum. The preparation however is principally used as an external application, having a degree of escharotic power, which renders it serviceable in venereal chancres, as well as in other ulcers having weak and spongy granulations; it is also very frequently employed to destroy fungous excrescencies, but it should be remembered that, as it owes such power to an excess of acid, unless it be carefully prepared, it must be inefficient. It ought to redden syrup of violets.
Alumen Rupeum. Roche or Rock Alum. This variety was originally brought from Roccha, formerly called Edessa, in Syria, in fragments of about the size of an almond, covered with an efflorescence of a pale rose colour; that however which is now sold under this name is common English alum, artificially coloured. It is unimportant.
Alumen Romanum. Roman Alum is in irregular octohedral masses, powdery on the surface; it is the purest kind, and contains no ammonia in its composition.
AMMONIACUM. L.E.D. (Heracleum Gummiferum.)
Ammoniac.
Qualities. Form, masses composed of fragments, of tears, yellow on the surface, and white within; Taste, a nauseous sweet, followed by a bitter flavour; Odour, faint but not unpleasant. Specific gravity, 1·200. Chemical Composition. Gum-resin, gluten, and some volatile matter. Solubility. It is partly soluble in water, vinegar, alcohol, æther, and in the solutions of the alkalies; when triturated with water a milky liquor is formed, which is a solution of gum holding the resin in suspension, and if the yolk of an egg be employed the mixture is more permanent; water appears to be its proper solvent. Uses. Stimulant, antispasmodic, and expectorant: in large doses gently purgative and sometimes diuretic; after the exhibition of smart purgatives, in combination with rhubarb, it proves valuable in mesenteric affections by correcting the viscid secretion of the intestines; dissolved in nitric acid, it is said to prove an excellent expectorant in cases where large accumulations of purulent or viscid matter exist with feeble and difficult expectoration. See Form: 140. Forms of Exhibition. In solution, see Mist: Ammoniac: it may also be given when dissolved in the Liquor ammoniæ acetatis; ʒij of the former may be dissolved in ℥iij of the latter; or it may be exhibited in pills with bitter extracts, myrrh, and other gum-resins; if rubbed with camphor a mass is at once produced very suitable for pills; vinegar renders it soft, and adapts it for plasters. Dose, grs. x to xxx. Officinal Preparations. Mist: Ammoniac: L.D. Pil: Scillæ co: L.E. (B) Emplast: Ammoniac: L. Emplast: Gummos: E. Emplast: Ammoniac: cum Hydrargyro. L. Adulterations. Two varieties are met with in the market, that in tears, guttæ ammoniaci, ought to be white, clear, and dry; and that in lumps, lapis ammoniaci, which sells for one-third the price of the former, being very impure, is generally adulterated with common resin, for which it may be purified by softening the mass in a bladder which is immersed in boiling water, and straining it while fluid.
AMMONIÆ SUB-CARBONAS. L. Carbonas Ammoniæ. E.D.
Sub-carbonate of Ammonia.