Characters. - A white, or nearly white, granular powder, very deliquescent, odourless, having a sharp saline and metallic taste, and an acid reaction.

Solubility. - Very soluble in water and in alcohol.

Reactions. - The aqueous solution yields a white precipitate with test solution of ferrocyanide of potassium or of sulphide of ammonium, a yellow precipitate with test solution of acetate of lead, and a red one with test solution of mercuric chloride (iodide).

Dose. - 1.2 to 2 grains.

Uses. - Locally it has been used in solution as an application to enlarged tonsils. An ointment, 1 part to 8 of lard, has been used in place of the ointment of iodide of potassium or of cadmium to reduce swellings. A solution of 2 grains to 1 oz. has been used in gonorrhoea. Internally it has been used in scrofula, chorea, and hysteria. It is best administered in the form of syrup.