DERIVATION.--Dissolve zinc in hydrochloric acid by boiling. The solution contains the zinc chloride with chlorides of iron and lead as impurities. These are precipitated by adding first nitric acid then zinc carbonate. Filter and finally evaporate. PROPERTIES.--A white, granular powder, or porcelain-like masses, irregular or moulded into pencils; odorless; of such intensely caustic properties as to make tasting dangerous unless the salt be dissolved in much water, when it has an astringent, metallic taste; very deliquescent; soluble in water and alcohol. LIQUOR ZINCI CHLORIDE--SOLUTION OF ZINC CHLORIDE DERIVATION.--Made from zinc chloride and water. It should contain about 50 per cent, by weight, of the salt. Zinc chloride is used externally only. PROPERTIES.--A clear, colorless, liquid, odorless, having a very astringent, metallic taste. ACTION AND USES.--Is caustic and escharotic, used full strength or in a strong solution; penetrates very deeply and causes deep sloughing; an irritant and corrosive poison; mild medical solutions are antiseptic and astringent; is also disinfectant and deodorizer. Can be used as a caustic when indicated; used with caution, for granulations in chronic ulcers and foot-rot in sheep; to slough out all kinds of fistula, usually mixed with one or two parts of flour made into a paste with water, two ounces in a pint of water is injected as a caustic into fistulous tracts; two or three per cent solution or two to four drachms to the pint of water is used for ordinary astringent purposes and as a parasiticide. VALUABLE DRUGS AND THEIR DOSES FOR DOMESTIC ANIMALS In the list of doses, oz. stands for ounce, pt. for pint, lb. for pound, gr. for grain, dr. for dram, dp. for drop.