Characters. - Colourless, clear, orthorhombic crystals or small needles, efflorescing and becoming opaque on exposure to air, no smell, very bitter taste, strongly acid reaction.

Solubility and Reactions. - It resembles the sulphate in its reactions, but is much more readily soluble. It dissolves with vivid blue fluorescence in 10 parts, while the sulphate requires 740 parts, of water at 59° F.

U.S.P. Quininae Hydrobromas. Hydrobromate of Quinine. C20H24N2O2HBr.2H2O; 440.8.

Characters. - Colourless, lustrous needles, no smell, very bitter taste, and a neutral or slightly alkaline reaction.

Solubility. - It is soluble in about 16 parts of water at 59° F.

Reactions. - The solution gives the reactions of quinine, and with test solution of nitrate of silver yields a white precipitate insoluble in diluted nitric acid, and in solution of carbonate of ammonium.

Action. - Useful for hypodermic injection. It is supposed to produce fewer unpleasant head symptoms than other preparations of quinine.