Each contains 60 grs. of ointment of mercury, benzoated lard and white wax each 20 grs., oil of theobroma 80 grs.

Uses. - They are employed where we wish to produce mercurial action without the risk of interfering with the digestion.

B.P. Unguentum Hydrargyri Compositum. Compound Ointment of Mercury. - Contains mercurial ointment (6), yellow wax (3), olive oil (3), and camphor (1 1/2).

The compound ointment is used to cause absorption of effusion or thickening around joints in cases of disease or injury after the inflammation has subsided. It ought to be combined with pressure and rest.

B.P. Linimentum Hydrargyri. Liniment of Mercury. - Vide p. 516.

Used for similar purposes as the plaster or ointment. It is more irritating than either, on account of the ammonia it contains.

It is said to cause salivation more readily than mercurial ointment, as the camphor and ammonia with which it is mixed assist its absorption.

Emplastrum Hydrargyri, B. and U.S.P. Mercurial Plaster.

Preparation. - Rub mercury with olive-oil, and sulphur B.P. or resin U.S.P., and add lead plaster to give it consistency. Sulphur and resin are used to extinguish the globules of mercury, i.e. make them so small as to be invisible.