Characters. - A light, white, amorphous powder, permanent in the air, odourless, tasteless.

Solubility. - It is insoluble in water or alcohol.

Impurities and Tests. - Wholly soluble in nitric or hydrochloric acid without effervescence (absence of carbonate). A solution of the salt in diluted nitric acid, after being mixed with an excess of acetate of sodium, yields a white precipitate with test solution of oxalate of ammonium (calcium), and a lemon-yellow precipitate with test solution of ammonio-nitrate of silver (phosphate).

Dose. - 1-20 grains. A simple way of giving it is to mix it with the salt used at meals.

Officinal Preparations

B.P.

U.S.P.

Dose.

It is contained in Pulvis Antimonialis.

Syrupus Calcii Lactophos-phatis.

1-4 fl. dr. (7.5-15 cc.).

U.S.P. Syrupus Calcii Lactophosphatis. Syrup of Lactophosphate of Lime. Made by dissolving freshly-precipitated phosphate in lactic acid, and mixing with orange-flower water and sugar (22 parts phosphate in 1,000).

Action. - Phosphate of calcium is an important constituent of the body, and occurs in considerable quantity wherever active cell-growth, either normal or pathological, is going on. It forms a large proportion of bones, and Chossat found that when animals were fed on food containing no lime-salts, the bones were soft. During pregnancy, fractures unite slowly, and Milne-Edwards found that when animals were supplied with abundance of phosphate of calcium fractures united more quickly.

It has been supposed that the constant use of fine flour tends to cause premature decay of the teeth, owing to the want of sufficient proportion of lime-salts. The decay of the teeth amongst Americans has been attributed to the perfection of their machinery, which completely separates the external parts of the grain and makes the flour exceedingly fine and white.

Uses. - It frequently lessens or removes toothache, especially that occurring in pregnancy or lactation (p. 353). It is useful in cases of chronic diarrhoea in children. It has been recommended in cases of rapid growth or deficient repair, as in growing children, anaemia, and debility from over-work, child-bearing, suckling, or diseases such as chronic abscess, diarrhoea, leucor-rhcea, bronchitis, and phthisis. It is frequently given in rickets with considerable benefit, although it is well to combine it with cod-liver oil. It is often advantageously given, along with iron, in the form of Parrish's Chemical Food, containing two and a half grains of phosphate of calcium and one grain of phosphate of iron in every drachm.