Prep. Lond. Mix mercury and sulphur in equivalent proportions, melt them over a fire, and as soon as the mass swells remove the vessel and strongly cover it lest the mixture take fire; then rub the mass to powder and sublime it. When melted sulphur is brought in contact with mercury, direct union ensues, the compound is afterwards sublimed, and forms artificial cinnabar.

Prop. & Comp. Dark scarlet shining crystalline masses, forming, when powdered, a beautiful scarlet colour, known by the name of vermilion; insoluble in water or alcohol. Volatilizes entirely when heated alone, but with potash it is reduced to metallic globules. Composition (Hg S).

Therapeutics. When the fumes are brought into contact with the surface of the body, the drug acts as a topical alterative and becomes absorbed, affecting the system the same as other mercurials; probably, when heated in the air, it is decomposed, at least in part. It is used as a fumigation in some syphilitic skin diseases, as ecthyma; also as an inhalation in venereal sore throat. Rarely or never used internally.

Dose. As a fumigating agent, 30 gr., heated on an iron plate and placed under the patient wrapped in a blanket; or the vapours may be applied to the mouth and throat through a funnel.

Adulteration. Red-lead, red oxide of iron, and brick-dust, detected by not subliming; occasionally red sulphuret of arsenic has been found, but this can be detected by heating with charcoal, when it gives off the garlic odour; also by the other tests for arsenic.