ZINC SULPHATE 239 



ZINC CARBONATE. Zinci Carbonas. Carbonate of Zinc. 



Calamine, the native carbonate, is an important ore of 

 zinc. The B.P. carbonate white, tasteless, and insoluble in 

 water is prepared by the interaction of zinc sulphate and 

 sodium carbonate, and is a mixture of carbonate and oxide 

 with water of crystallisation, Zn CO 3 (Zn H 2 2 ) 2 H 2 O. Its 

 uses are identical with those of the oxide. 



ZINC SULPHATE. Zinci Sulphas. Sulphate of Zinc. White 

 Vitriol. ZnS0 4 7H 2 0. 



Zinc blende, the native sulphide when roasted, yields a 

 crude sulphate. The B.P. salt is formed by the interaction 

 of diluted sulphuric acid and zinc. It occurs in colourless, 

 transparent, tabular crystals, isomorphous with those of 

 Epsom salt, with a styptic metallic taste, and efflorescent in 

 dry air. It is soluble in 2' 5 parts of alcohol (90 per cent.), 

 and in two parts of water. 



ACTIONS AND USES. It is irritant, emetic, astringent, and 

 antiseptic internally. It is used externally as a stimulant, 

 astringent, and antiseptic. 



Toxic ACTIONS. Powerful astringent effects are produced 

 on horses by sixty to seventy-five grains ; three to five 

 drachms dry the buccal and gastro-intestinal secretions, and 

 cause nausea, colic, and efforts to vomit (Tabourin). Two 

 horses had each half an ounce daily for a fortnight without 

 marked effect, but larger doses impaired appetite, and caused 

 nausea and diuresis. Somewhat larger doses produce similar 

 effects on cattle. Dogs receiving seven to thirty grains 

 promptly vomit ; but the act is seldom accompanied by the 

 nausea and depression produced by tartar emetic. Orfila 

 found that seven and a half drachms were vomited by dogs 

 in a few seconds, but produced no lasting bad effects. 

 When vomiting, however, was prevented by ligature of the 

 oasophagus, much smaller quantities sufficed to destroy dogs, 

 in about three days, from gastro-enteritis. Thirty grains 

 in solution, injected into the veins, depressed the action of 

 the heart and destroyed life in a few seconds (Christison). 

 Repeated doses are detected in the spleen, liver, faeces, and 



