Mercuric Ethyl Chloride (Hydrargyrum æthylo-chloratum) is used as a medicine on the Continent. It occurs in white, glittering, crystalline scales, which take on pressure a metallic appearance, and possess a peculiar ethereal odour; it is but little soluble in water and ether, with difficulty in cold alcohol, but copiously soluble on boiling, and depositing crystals on cooling. It sublimes at about 40° without residue; on quick heating it burns with a weak flame, developing a vapour of metallic taste and unpleasant odour. It gives no precipitate with silver nitrate, nor with albumen.
Corrosive Sublimate (Mercuric chloride), HgCl2 = 271; Hg, 73·8 per cent., Cl, 26·1 per cent.—In commerce this salt occurs in transparent, heavy, colourless masses, which have a crystalline fracture; if placed in the subliming cell described at [p. 258], it sublimes at about 82·2° (180° F.), and melts at higher temperatures. The sublimate is generally in groups of plates drawn to a point at both ends, in crystalline needles, or in octahedra with a rectangular base. It dissolves in 16 parts of cold water and about 3 of boiling, and is very soluble in solutions of the alkaline chlorides; it dissolves also in ether, and can be, to a great extent, withdrawn from aqueous solutions by this agent. Alcohol dissolves nearly one-third its weight of the salt, and its own weight when boiling. It combines with albumen; gives, when in solution, a precipitate of mercuric oxide when tested with solution of potash; a white precipitate with ammonia; a scarlet with iodide of potassium; and a black precipitate of finely divided mercury with protochloride of tin. If a crystal (when placed in the subliming cell) gives a crystalline sublimate at about the temperature mentioned, and this sublimate becomes of a red colour when treated with a droplet of iodide of potassium, it can be no other substance than corrosive sublimate.
Solution of Perchloride of Mercury (Liquor hydrargyri perchloridi) is simply 10 grains of perchloride of mercury and chloride of ammonium in a pint of water; 100 c.c. therefore should contain 114 mgrms. corrosive sublimate.
Yellow Mercurial Lotion (Lotio hydrargyri flava).—Perchloride of mercury, 18 grains, mixed with 10 ounces of solution of lime.
Calomel[903] (Hydrargyri subchloridum).—The properties of calomel have been already [described]. It sometimes contains as an impurity corrosive sublimate, which may be dissolved out by ether. Carbonate of lead, sulphate, and carbonate of baryta, gum, and starch, are the usual adulterants mentioned. If on the application of heat calomel entirely sublimes, it must be free from the substances enumerated.
[903] It would appear that in America a cosmetic is in use, consisting of calomel mixed into a paste with water.—Vide “A Dangerous Cosmetic,” by C. H. Piesse, Analyst (25), 1878, p. 241.
Oleate of Mercury (Hydrargyri oleatum) is composed of 1 part of yellow oxide and 9 parts of oleic acid.
Black Mercurial Lotion (Lotio hydrargyri nigra).—Calomel, 30 grains, mixed with 10 fluid ounces of lime-water.