Prop. & Comp. It occurs in whitish masses, quite white when pure; of a caustic taste; rapidly absorbing water and becoming hydrated or slaked; and also carbonic acid, and re-forming chalk. When two-thirds of its weight of water are poured upon it, it slakes rapidly with development of much heat, and is converted into a snow-white and very bulky powder. About 11 grains are dissolved by a pint of water at 60° Fah.; it is less soluble in boiling water; sugar greatly increases its solubility. The solution of lime has an alkaline reaction, and yields a white precipitate with oxalate of ammonia; it soon absorbs carbonic acid if exposed to the air. Lime, if previously slaked, dissolves in dilute hydrochloric acid without effervescence, and if this solution be evaporated to dryness, and the residue re-dissolved in water, only a very scanty precipitate forms on the addition of saccharated solution of lime.
Off. Prep. Calcis Hydras. Slaked Lime. Recently prepared lime slaked with water.
Liquor Calcis. Solution of Lime; lime Water. (Slaked lime, two ounces; distilled water, one hundred and sixty ounces. Keep the solution in stoppered glass vessels; and when it is to be used, draw off the clear solution with a syphon.) Ten fluid ounces require for neutralization at least twenty measures of the volumetric solution of oxalic acid, which correspond to about five grains and a half of lime; or about half a grain to the ounce.
Liquor Calcis Saccharatus. Saccharated Solution of Lime. [Not officinal in U. S. P.] (Slaked lime, one ounce; refined sugar, in powder, two ounces; distilled water, twenty fluid ounces.) Sp. gr., 1.052. One fluid ounce requires for neutralization 25.4 measures of the standard solution of oxalic acid, which correspond to 7.11 grains of lime.
Linimentum Calcis. Liniment of Lime. (Lime-water, olive oil, each, two fluid ounces; shake them together until they are mixed.) [Solution of lime, 8 fl. ounces; flax seed oil, 7 troy ounces. Mix them.]
Lime forms also a part of Potassa cum Calce, not now officinal.
Therapeutics. Lime is only given as liquor calcis, which acts as an antacid both on the intestinal canal, and, after absorption, on the blood and secretions. It differs, however, from potash and soda, in being astringent or desiccative, diminishing secretion, and hence is very useful in diarrhoea connected with acidity, and in some cases of dyspepsia; it has also been used in certain calculous affections. Externally applied, lime acts as a caustic, or much diluted, as a desiccative, and is applied to burns in the form of linimentum calcis.
Dose. Of liquor calcis, 1/2 fl. oz. to 2 fl. oz. or more, with milk, etc.; of liquor calcis saccharatus, 15 min. to 1 fl. drm.
Adulteration. Lime and liquor calcis are apt to contain carbonic acid and metallic impurities, which can be detected by the tests given above.