184 ^ INORGANIC AGENTS 



ZiNCi OxiDUM. Zinc Oxide. Zn O. (U. S. & B, P.) 



Derivation. — Heat the carbonate to redness. 



2 (Zn CO,), Zn(OH), = 8 ZnO + 2 H,0 + 6 CO,. 



Properlies. — An amorphous, white po-w'der, without odor 

 or taste. It gradually absorbs carbon dioxide from the air. 

 Insoluble in water or alcohol. 



Dose.—'R. & C, 3 i--ii- (4.-8.); I>-, gr.v.-x. (.3-.6). 



PRBPARATION. 



Unguentum Zinci Oxidi. Ointment of Zinc Oxide. (TJ. S. P.) 

 Zinc oxide, 200 ; benzoinated lard, 800. (XJ. S. P.) 

 Unguentum Zinei. 15 per cent, of zinc ointment. (B. P.) 



ZiNCi AcETAS. Zinc Acetate. Zn (C^HsO,), + 2 HjO. 

 (U. S. & B. P.) 



Derivation. — Dissolve zinc oxide in diluted acetic acid 

 and boil. 



ZnO + 2 HGMfi, = Zn (GJifi,), + H,0. Evaporate 

 and crystallize. 



Properties'. — Soft, white, six-sided monoclinic plates, of 

 a pearly lustre, having a faintly acetous odor, and an astrin- 

 gent metallic taste. Exposed to the air the salt gradually 

 effloresces and loses some of its acid ; reaction acid ; soluble 

 in 2.7 parts of water and in 36 parts of alcohol. 



Incompatibles . — Same as sulphate. 



Dose. — Same as sulphate. 



ACTION OF THE ZINC SALTS. 



External. — The salts of zinc (except the chloride) have 

 an astringent action on raw surfaces and mucous membranes 

 in precipitating solutions of proteids, as zinc albuminate, 

 notably the sulphate and acetate. Absorption is not followed 

 by poisoning, as most of the zinc is stored in the liver. 

 They resemble other astringents, especially copper salts, 

 and are more irritating than lead acetate or subacetate. 



Internal. — In the alimentary tract very large doses of 

 the sulphate or acetate may induce gastro-enteritis, which 

 is to be treated with demulcents and alkaline carbonates in 



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