Glycerine, discovered in 1789 by Scheele, who gave it the name of the "sweet principle of oils," is a thick and syrupy liquid produced by the saponification of the fats and fixed oils. It is either colorless, or of a pale amber tint, unctuous, inodorous when pure, and very sweet to the taste, whence the current appellation. The sp. gr. is 1.260; the composition is C9H8O3. It contains a small percentage of water.

(From a chemical standpoint, glycerine belongs to the alcohol series, and experimentally has been found to produce symptoms resembling those of alcohol. In animals intoxication follows the ingestion of large doses, and, if they be excessive, death, preceded by coma, is the result.)

Glycerine does not become rancid: it does not evaporate, but with heat it decomposes, with evolution of intensely irritating vapors, and at a full red heat ignites and burns with a blue flame. When submitted to strong heat in a capsule, it leaves no residue. With water and with alcohol it mixes readily, dissolving in each of these in any proportions, but in ether it is not soluble. It dissolves, in turn, a great variety of different substances, such as iodine, common salt, the fixed alkalies, the vegetable acids, tannic acid in particular, and many of the salts of the vegetable alkalies. Hence it becomes an excellent recipient of many medicinal matters. To lotions it is a very useful adjunct, by reason of its soft and unchanging oiliness: it is excellent also as a simple lubricant for dry, chapped, or slightly abrased skin, and in cases of deafness, either alone or in combination with olive oil. It has been tried as a substitute for cod-liver oil, but not satisfactorily.

(Its internal use has been recommended on insufficient theoretical grounds in some forms of acne, and from reports appears to have been somewhat useful.)

Preparations and Dose. - Glycerina, 3 ss. - j. (2.50 - 5.).