Origin. - A liquid obtained by the decomposition of vegetable or animal fats or fixed oils, and containing not less than 95 per cent. of absolute glycerin.

Description and Properties. - A clear, colorless liquid, of a thick, syrupy consistence, oily to the touch, odorless, very sweet and slightly warm to the taste. When exposed to the air it slowly abstracts moisture. Specific gravity not less than I.246. Soluble in all proportious in water or alcohol; also soluble in a mixture of 3 parts of alcohol and I part of ether, but insoluble in ether, chloroform, carbon disul-phide, benzin, benzol, and fixed or volatile oils.

Dose. - 5-60 minims (0.3-4.0 Cc.) [1 fluidram (4 Cc), U. S. P.].

Official Preparations

Glyceritum Amyli - Glyceriti Amyli - Glycerite of Starch. - Starch, 10; water, 10; glycerin, 80.

Used internally or externally.

Suppositoria Glycerini - Suppositoria (acc.) Glycerini - Suppositories of Glycerin. - Each suppository contains 93 grains (6.0 Gm.) of glycerin.

Used as required.

Gelatinum Glycerinatum - Gelatini Glycerinati - Glycerinated Gelatin. - A mixture of equal parts of gelatin and glycerin. The mass when cold is solid, but easily melts on applying gentle heat.

Basis for suppositories and bougies.

Of late years both ointments and cerates have been largely superseded, especially in Europe, by dertamologic pastes and glycerogelatins. The former are mixtures of the medicinal agents with starch, dextrin, or kaolin, and glycerin, soft soap, petrolatum, or lard, and are intended chiefly for antiseptic, astringent, or germicidal effects. The glycero-gelatins are firmer than the pastes, and must be melted before they can be applied (Hunt).

Glycerin is also contained in the following official preparations:

Glyceritum Phenolis, Glyceritum Acidi Tannici, Glyceritum Boroglycerini, Glyceritum Hydrastis, Mucilago Tragacanthae, Massa Hydrargyri, Pilulae Phosphori, and in many extracts and fluidextracts.

Antagonists and Incompatibles. - Glycerin is incompatible with potassium permanganate and with chromic acid.

Synergists. - Its emollient properties may be enhanced by other emollients and demulcents.

Physiological Action. - Externally and Locally. - When glycerin is applied to the skin or mucous membrane it is ordinarily bland and unirritating, although in certain cases the drug occasions a sensation of burning and smarting, which may be due either to an impure preparation, the rapid- absorption of water from the tissues, or merely to a marked idiosyncrasy on the part of the patient. Should the pure drug show a tendency to irritate the skin, the glycerin should be properly diluted with water.

Preparations more concentrated than the specific gravity recommended by the U. S. Pharmacopoeia - viz. 1.246 - should be avoided, because of their irritating properties.

Glycerin abstracts water from the tissues, and is rapidly absorbed through the skin. It possesses marked diffusive power, being capable of diffusing itself freely over and through organic matter.

Internally. - The principal action of glycerin when taken internally is that of a purgative. The drug purges when given by the rectum, either as an enema or in the form of a suppository.

Glycerin is readily absorbed from the alimentary canal, and it is thought to undergo oxidation, thereby acting as a food and increasing body-weight. Some competent investigators allege that it is not in the least degree nutritious.

When immoderate amounts of the drug are taken, it may be detected in the urine, while under excessive doses effects may be produced similar to those resulting from alcoholic poisoning.

Following the ingestion of very large doses, there may be extreme muscular weakness, dryness of mucous membranes, dark-colored urine, collapse, and death. The drug is not considered poisonous, excessive amounts being necessary to produce the symptoms above described.

Therapeutics. - Externally and Locally. - Glycerin is a popular and efficient remedy for chapped hands and slight excoriations.

Fissured nipples and fissure of the anus are well treated with pure glycerin or with glycerin and tannic acid. The drug also makes an efficient application to bedsores.

Glycerin is employed as an injection in gonorrhea. It may be used alone or medicated with bismuth subnitrate or with extract of opium.

Glycerin is one of the best solvents for hardened cerumen, and tampons wet with glycerin or with glycerite of tannic acid are very serviceable in leucorrhea and erosion of the cervix, and endometritis with congestion and subinvolution of the uterus.

Glycerin possesses marked antipruritic properties, and, whether applied pure or combined with oils or ointments, will allay itching of most affections of the skin.

Lotions or diluted aqueous solutions of glycerin are frequently employed in various diseases of the ear, nose, and throat, such as fissure of the tongue, chronic laryngitis, chronic nasal catarrh, coryza, pharyngitis, etc.

A mixture of glycerin and water will lessen or prevent dryness of the mouth from fever or other causes.

Glycerin is an efficient topical remedy for the reduction of edema of the prepuce, and is a serviceable antiseptic dressing for wounds, carbuncles, boils, etc.

Glycerite of starch is an excellent soothing emollient in acute eczema, and quite an efficient preparation to prevent pitting in variola.

Internally. - The principal internal use for glycerin is for the relief of habitual constipation, being far more efficient in habitual, than in occasional, constipation, and more generally applicable to females than to males, and to those cases where the fecal mass is retained in the rectum than in the sigmoid flexure or above it. For the purpose of relieving constipation it may be given by the mouth, alone or associated with castor oil, or I or 2 fluidrachms (4.0-8.0 Cc.) injected into the rectum, or, which perhaps is the emollients, demulcents, protective agents. most agreeable method, by the insertion into the rectum of a