Prep. Hydrochlorate of ammonia is distilled with slaked lime, and the resulting ammonia (gas) passed into distilled water, which absorbs it with intensity, and forms the solution of ammonia.

Prop. & Comp. The strong solution has a sp. gr. 0.891, [pp. gr. 900, and containing 26 per cent. of the gas. U. S.] is colourless, giving off pungent fumes when exposed to air, and has a strong alkaline reaction. When diluted with four times its volume of distilled water no colour or precipitate should be produced by sulphuretted hydrogen or lime-water, by oxalate of ammonia, or ammonio-sulphate of copper; showing the absence of most ordinary metallic impurities, carbonic acid, lime, or arsenic; the solution, when treated with an excess of nitric acid is not rendered turbid by nitrate of silver or chloride of barium, indicating freedom from chlorides, or sulphates. One fluid drachm requires for neutralization 102 measures of the volumetric solution of oxalic acid. It contains therefore a fraction more than 17 grains (an equivalent) of ammonia in the fluid drachm.

Off. Prep. Liquor Ammoniae. Solution of Ammonia. [Aqua Ammonia). Water of Ammonia. U. S.] (Strong solution of ammonia, twenty fluid ounces; distilled water, forty fluid ounces.) Sp. gr. 0.959. [Sp. gr. 0.960.] One fluid drachm requires for neutralization 30.8 measures of the volumetric solution of oxalic acid. It is about one-third of the strength of the strong solution.

Linimentum Ammoniae. Liniment of Ammonia. (Solution of ammonia, one fluid ounce; olive oil, three fluid ounces.) [Two troy ounces. U. S.] Strong solution of ammonia is also an important ingredient in Linimentum Camphorae Compositum.

Therapeutics. In medicinal doses free ammonia, as exhibited in any of its preparations, produces warmth at the epigastrium, and acts as an antacid; increases the force and frequency of the pulse, allays spasm, and promotes the secretions from the skin and mucous membranes, especially the bronchial. In larger doses throbbing and pain in the head, with heaviness, are induced; and in still larger medicinal doses, emetic effects; beyond this, poisonous irritant symptoms may be caused. The action of ammonia differs much from that of alcohol, probably influencing the ganglionic and spinal systems rather than the brain proper, and increasing the functions of the secreting and excreting organs. It does not render the urine alkaline, but perhaps a portion appears in that fluid as nitric acid. Externally applied, ammonia is rubefacient, and even vesicant; inhaled as a gas, it is topically irritant.

Ammonia is given to rouse the system in syncope; to diminish spasm in hysteria; to relieve nervous headache, the after-effects of alcohol, and delirium tremens; also as a stimulant in low states of the system, as typhoid forms of fever; in pneumonia and bronchitis, in which latter the expectorant power is also useful; as a stimulant and antacid in low forms of dyspepsia connected with increased secretion of acid and flatulence in the stomach. Externally it is employed to the mucous membrane of the nose in syncope and insensibility (in such cases care should be taken not to use too strong solutions); also occasionally it is inhaled, very much diluted, as an expectorant in chronic bronchitis. On the skin it is used, combined with volatile or essential oils, in most cases where a counterirritant effect is desired to be produced by means of an embrocation, as over painful parts, stiff joints, etc. Liquor ammonias fortior, rubbed up with lard, will vesicate rapidly, if evaporation is prevented. Ammonia may be used with advantage in poisoning with prussic acid, digitalis, tobacco, colchicum, and other sedative drugs.

Dose. Of liq. [aqua. U. S.] ammonias (not fortior) 10 min. to 30 min., well diluted. The dose of the strong solution is one-third of that amount.