Characters. - A colourless liquid, with a characteristic and very pungent odour, and strong alkaline reaction. Specific gravity 0.891.

Preparations in which Strong Solution of Ammonia is used.

B.P

Ammonii Phosphas.

Linimentum Camphorae Corapositum (p. 516).

Liquor Ammoniae.

„ Ammonii Citratis Fortior. Spiritus Ammoniae Aromaticus,

„ „ Foetidus.

Tinctura Opii Ammoniata.

U.S.P

Spiritus Ammoniae.

Action and Uses. - When applied to the nose, the vapour of strong ammonia acts as a powerful irritant. It stimulates the nasal branches of the fifth nerve, and thus reflexly excites the vaso-motor centre and raises the blood-pressure. It thus tends to prevent or to remove conditions of shock and syncope. When applied for too long a time, or in too concentrated a form, it may produce inflammation of the mucous membrane and respiratory passages. Applied to the skin it quickly evaporates, and has but a slight rubefacient effect, but when its evaporation is prevented it passes through the epidermis and acts as a powerful vesicant. When swallowed in large quantities, and undiluted, it may produce gastro-enteritis, but on account of the vapour gaining access to the air-passages and causing immediate suffocation, it may cause death in a few minutes. Along with the 3gastro-enteritis there may be comatose symptoms due to the action of the drug itself on the brain after absorption, and in this it differs from poisoning by caustic potash or soda. It stimulates the circulation reflexly through the nerves of the stomach, and after its absorption stimulates both the respiration and circulation by its direct action upon the circulatory and respiratory nerve-centres.

Uses. - Inhalation of its fumes is used to prevent drowsiness or fainting, or to recover persons from a faint, or from shock, or from the narcosis produced by opium, syncope, or the depression caused by vascular sedatives. It should not be applied for too long a time, lest bronchitis be induced. It is sometimes employed in a milder form to cut short nasal catarrh, to lessen pain in the nose and forehead, and diminish the expectoration in chronic bronchitis. It is used as a counter-irritant to the skin in rheumatic pains, stiffened rheumatic joints, and bronchitis. As a vesicant it may be employed where the use of cantharides is objectionable. A pledget of lint, somewhat larger than the blister desired, is moistened with ammonia, covered with a watch-glass, and applied to the skin until a red ring forms round the glass. The pledget is then removed and a poultice applied. The poison of nettles and insects is frequently of an acid character, and ammonia rubbed over the part stung will lessen the pain and swelling. The injection of ten drops of strong liquor ammoniae, diluted with three parts of water, into the veins, has been recommended in cases of snake-bite. It may be useful possibly in bites of less poisonous snakes, but is of no utility in bites by the cobra or daboia. It may be given internally, diluted, as a stimulant in cases of syncope, and in the depression, weakness, and faintness to which some women are subject. In these cases the liquor ammoniae may be employed as a substitute for alcohol, and thus the tendency to contract habits of drinking may be counteracted. It may be used, like other alkalis, to stimulate the secretion of gastric juice, and especially where we do not wish to diminish the acidity of the urine or render it alkaline, and also where we wish to stimulate the nervous system, as in cases of anaemia and debility, and more especially where the stomach is relaxed and distended with gas. It also stimulates the intestines, and aids the expulsion of gas from them. It is therefore very useful in the flatulence and colic of children. It may be employed to lessen the watery discharge from the bowels where this persists after the removal of the irritant which has caused it.