298 MERCURIC CHLORIDE 



MERCURIC CHLORIDE. HydrargyriPerchloridum. Bichloride 

 of Mercury. Corrosive Sublimate. HgCl 2 . 



Corrosive sublimate and calomel are both chlorides of mer- 

 cury ; corrosive sublimate contains twice as much chlorine 

 as calomel, is the higher, per-, or mercuric chloride (HgCl 2 ), 

 and is a soluble and actively corrosive poison ; while calomel, 

 the lower or mercurous chloride (Hg 2 Cl 2 ), is an insoluble, 

 and therefore comparatively mild agent. By using, in 

 speaking or writing, the vernacular names, risk of mistaking 

 these chlorides is diminished. 



Corrosive sublimate may be prepared by heating a mixture 

 of mercuric sulphate, sodium chloride, and a little black 

 oxide of manganese. 



It occurs in heavy, colourless masses of prismatic crystals, 

 devoid of odour, but with an acrid, metallic taste. When 

 heated it sublimes without decomposition, leaving only a 

 trace of fixed residue. It is soluble in about three parts of 

 alcohol (90 per cent.), four parts of ether, two parts of 

 glycerin, two of boiling water, and sixteen of cold water, 

 or nearly four grains to the ounce. Its solubility is increased 

 by the presence of certain salts, such as the chlorides of 

 sodium and ammonium. Its antiseptic properties recom- 

 mend it for preserving anatomical preparations. It is nqt 

 subject to intentional adulteration. 



ACTIONS AND USES. It is a corrosive and irritant poison ; 

 is occasionally prescribed as an alterative and antiseptic ; 

 repeated doses cause mercurialism. Externally, it is used 

 as an antiseptic, astringent, caustic, and parasiticide. 



Corrosive sublimate precipitates albumin, the precipitate 

 being dissolved by excess of proteid, and hence in powder 

 or concentrated solution is irritant and corrosive, for the 

 protective scum of albumin is removed, and the drug pene- 

 trates farther. Dissolved in water, it is the most energetic 

 antiseptic ; one part in 25250 prevents the development of 

 bacteria taken from meat infusion ; one part in 10250 

 prevents the development of spores in boiled meat infusion ; 

 one part in 6500 prevents reproduction of spores (Koch). 

 Spores placed in one per thousand solution in water are 

 effectually destroyed in one to two days. Solution of one 



