Characters. - Colourless, transparent, tabular, rhombic crystals, slowly coloured yellow by exposure to light, slightly efflorescent in dry air, odourless, having a mildly saline and somewhat bitter taste, and a slightly alkaline reaction.

Reactions. - The aqueous solution, on the addition of hydrochloric acid, deposits a crystalline precipitate, which is soluble in chloroform, and which yields, with alcoholic solution of potassa, a scarlet-red liquid gradually becoming colourless.

Dose. - 8 to 10 grains.

Uses. - This substance has been introduced into the U.S.P. as an anthelmintic.