=*Hydrargyri Chloridum Corrosivum (Hydrarg. Chlor. Corr.), Corrosive Mercuric Chloride, U.S.P.= (Bichloride of Mercury, Corrosive Sublimate, Mercuric Chloride, Perchloride of Mercury).--HgCl{2}. Heavy, colorless crystals, crystalline masses or white powder, odorless and with a characteristic metallic taste. Slowly soluble in water (1:13.5) and freely soluble in alcohol (1:3.8). Its solubility in water is increased by the addition of sodium or ammonium chloride. Incompatible with soluble carbonates and hydroxides, with iodides and with alkaloids and other organic compounds. Reduced to calomel or metallic mercury by iron, zinc and other reducing agents. ACTION AND USES: Chiefly as a germicide and antiseptic; also as a specific antisyphilitic agent. Acute mercuric chloride poisoning is treated by raw eggs and lavage. DOSAGE: 0.003 Gm. or 1/20 grain (U.S.P.) in solution or pills. For hypodermic use in syphilis 0.01 Gm. or 1/6 grain daily (produces marked pain and irritation). As antiseptic externally in solution from 1:20,000 to 1:2,000. As disinfectant of clothing, in 1:1,000 solution. _Mulla Hydrargyri Chloridi Corrosivi (Mull. Hydrarg. Chlor. Corros.), Corrosive Mercuric Chloride Mull, N.F._ (Unguentum Hydrargyri Chloridi Corrosivi Extensum, N.F. III).--Corrosive mercuric chloride (0.2%), alcohol, benzoinated suet and benzoinated lard. _Toxitabellae Hydrargyri Chloridi Corrosivi (Toxitabel. Hydrarg. Chlor. Corr.), Poison Tablets of Corrosive Mercuric Chloride, U.S.P._ (Corrosive Sublimate Tablets, Bichloride Tablets).--Tablets of an angular shape colored blue, each having the word "Poison" and the skull and cross bones design distinctly stamped on it. Each 1 Gm. tablet contains about 0.5 Gm. or 8 grains corrosive mercuric chloride and 0.5 Gm. or 8 grains sodium chloride. =*Hydrargyri Chloridum Mite (Hydrarg. Chlor. Mit.), Mild Mercurous Chloride, U.S.P.= (Mercurous Chloride, Calomel, Protochloride of Mercury, Subchloride of Mercury).--HgCl. White or nearly white, odorless, tasteless powder. Insoluble in water, alcohol or ether. Incompatible with alkalies, with oxidizing acids like nitric acid, and with soluble bromides and iodides. ACTION AND USES: A slow cathartic, fairly powerful and relatively non-irritant. Should usually be followed by a saline laxative. Should not be taken continuously as it may salivate. Also employed as a diuretic in cardiac dropsies. Intramuscular injections are very efficiently antisyphilitic, but painful. DOSAGE: Laxative, 0.15 Gm. or 2-1/2 grains (U.S.P.); alterative, 0.015 Gm. or 1/4 grain (U.S.P.). From 0.005 to 0.02 Gm., or from 1/12 to 1/3 grain, may be given every half hour or hour until from 0.1 to 0.2 Gm., or from 1-1/2 to 3 grains have been given. In the treatment of syphilis 0.1 Gm. or 1-1/2 grain in oily suspension is injected about once a week.