2. Mercuric chloride and ammonium chloride, of each 1⁄2 lb.; water, 3 quarts; dissolve,
and precipitate with solution of potassium hydrate, q. s.
Prop., &c. A white, inodorous, light mass, or powder; insoluble in alcohol, partially soluble in boiling water, and wholly dissolved by sulphuric, nitric, and hydrochloric acids, without effervescence. It is totally dissipated by heat. When heated with solution of potash, it exhales ammonia, and assumes a yellow colour. Used to make an ointment, which is employed in herpes, porrigo, itch, and other skin diseases, &c.; and by the lower orders as a dusting powder to destroy pediculi, an application which, from its liberal employment, is not always a safe one. It is highly poisonous, and must not be swallowed.
Mercuric and Ammonium Chloride. NH4Cl,HgCl2. Syn. Chloride of mercury and ammonium, Sal alembroth; Hydrargyri et ammonii chloridium, L. Prep. (P. Cod.) From mercuric chloride and ammonium chloride, equal parts, triturated together. “The object in adding the ammonium chloride here is to render the corrosive sublimate more soluble in water. The action of the latter is not otherwise altered.” (Redwood.) It is chiefly used for lotions and injections.
Mercuric and Quinine Chloride. Syn. Chloride of mercury and quinine; Hydrargyri et quinæ chloridum, L. Prep. (M’Dermott.) From mercuric chloride, 1 part; quinine chloride, 3 parts; separately formed into saturated solutions with water and then mixed; the crystalline precipitate is collected and dried by a gentle heat.—Dose, 1⁄8 to 1⁄2 gr., made into a pill with crum of bread; daily, as an alterative in debilitated habits; or combined with opium thrice daily, to produce salivation.
Mercuric Cyanide. HgCy2 or Hg(CN)2. Syn. Cyanide of mercury; Hydrargyri cyanidum, H. bicyanidum, H. cyanuretum (Ph. U. S.), L. Prep. 1. (Pb. L. 1836.) Ferric ferrocyanide (pure Prussian blue), 8 oz.; mercuric oxide, 10 oz.; distilled water, 4 pints; boil for half an hour, filter, evaporate, and crystallise; wash what remains frequently with boiling distilled water, and again evaporate, that crystals may form. This is Proust’s process. The formula of the Ph. U. S. is similar.
2. (Ph. D. 1826.) Prussian blue (pure), 6 parts; mercuric oxide, 5 parts; distilled water, 40 parts; as the last.
3. (Desfosses.) Potassium ferrocyanide, 1 part, is boiled for 1⁄4 hour with mercuric sulphate, 2 parts, and distilled water, 8 parts; the deposit is separated by filtration, and the liquid evaporated to crystallising point.
4. (Winckler.) Saturate dilute hydrocyanic acid with mercuric oxide; evaporate and crystallise. Pure.
Prop., &c. Heavy, colourless, inodorous, square prisms; tasting strongly metallic; soluble in 8 parts of cold water; slightly