"Take of sublimed sulphur, one part; water of caustic potassa, eleven parts. Boil them together for ten minutes, and filter through paper. Preserve the preparation in well-stopped phials. The specific gravity of this liquor is, to that of distilled water, as 1117 to 1000."

Syn. Liquore di Solfuro di Potassa (I.).

The name given to this preparation conveys an erroneous idea of its nature. When an alkaline sulphuret is dissolved in water, changes exactly similar to those which take place during the solution of an earthy sulphuret occur, altering the character of the product; and as the same happen by the direct combination of sulphur with a liquid alkali, this preparation is not a simple aqueous solution of sulphuret of potassa, but, in fact, a solution of the metallic base of the alkali in sulphureted hydrogen, or a hydrosulphuret of potassium.

Qualities. - This solution has a slightly foetid odour, and a nauseous, acrid, bitter taste. Its colour is reddish yellow, approaching to deep orange; its feel soapy; and it stains the cuticle a greenish black. Acids decompose it, precipitating the sulphur, and disengaging a portion of sulphureted hydrogen gas; and it is also decomposed by exposure to the air, the oxygen of which being absorbed by the sulphur forms sulphuric acid, which produces a sulphate with the potassa; so that in process of time the whole is changed into a solution of sulphate of potassa. Hence the necessity of preserving it in well-stopped phials."

1 Pearsons Practical Synopsis, etc. i. 283.

2 It was formerly denominated liquid hepar, or liquid liver of sulphur.

Medical properties and uses. - This solution does not differ in its medicinal properties from the solid sulphuret of potassium. It is, however, chiefly employed as an external application; and as such has been found very beneficial - in porrigo, scabies, and herpetic eruptions. When given internally, the dose is from til. xx. to 3iss. twice a day.