Origin. - Bismuth subnitrate and citric acid are boiled in sufficient water, and the precipitate washed and dried. It should contain not less than 58 per cent. nor more than 60 per cent. of pure bismuth oxide.

Description and. Properties. - A white, amorphous or microcrystalline powder, odorless and tasteless, permanent in the air. Insoluble in water or alcohol, but soluble in ammonia water and in solutions of the citrates of the alkalies.

Dose. - 1-3 grains (0.06-0.2 Gm.) [2 grains (0.125 Gm.), U. S. P.].

Official Preparation

Bismuthi et Ammonii Citras - Bismuthi et Ammonii Citratis - Bismuth and Ammonium Citrate. - Origin. - Prepared by mixing bismuth citrate with distilled water to make a paste, adding sufficient ammonia water to make a solution, filtering, evaporating, and drying on plates of glass.

Description and Properties. - Small, shining, pearly or translucent scales, odorless, with a slightly acidulous and metallic taste, becoming opaque on exposure to the air. Very soluble in water, but sparingly soluble in alcohol. The product should be kept in well-stoppered bottles, protected from light.

Dose. - 1-10 grains (0.06-0.6 Gm.) [2 grains (0.125 Gm.), U. S. P.].