Origin. - Prepared by dissolving purified bismuth in nitric acid and water, concentrating by evaporation, adding more water, stirring well, and washing and drying the precipitated bismuth subnitrate. It should yield not less than 80 per cent. of pure bismuth oxide.

Description and Properties. - A heavy, white powder, of somewhat varying chemical composition, odorless and almost tasteless, permanent in the air. Nearly insoluble in water and insoluble in alcohol, but readily soluble in nitric or hydrochloric acid.

Dose. - 5-20 grains (0.3-1.2 Gm.) [7 1/2 grains (0.5 Gm.), U. S. P.].