62 VETEEINAEY TOXICOLOGY 



The oxide and carbonate are extensively used as pigments 

 — zinc white — and in antifouling preparation for ships. 

 They and the salts of weak acids, such as zinc acetate and 

 zinc henzoate, are astringents, and are used internally in 

 medicine. 



Zinc cisterns and galvanised vessels yield zinc to soft 

 water under the same conditions as those governing the 

 solution of lead. It is not to be apprehended that poisoning 

 would arise from this cause. 



The metal is also dissolved, probably by means of organic 

 acids, from zinc-lined troughs, and on this account is fre- 

 quently found in forage and foodstuffs. 



In spite of the wide diffusion of zinc compounds poisoning 

 is only likely to occur from the accidental administration of 

 zinc chloride, or of the sulphate. In the latter case dogs 

 and cats promptly reject the dose by vomiting, and under 

 proper treatment a fatal termination is unlikely. 



Absorption and Elimination. — The insoluble compounds 

 of zinc are not very easily absorbed, being found only in 

 traces in the organs after lengthy dosage. The greater part 

 of a dose of the oxide is excreted as sulphide in the faeces. 

 The soluble and irritant salts are absorbed, and may be 

 found in the liver, kidneys, and spleen. Elimination takes 

 place chiefly by the kidneys, but zinc is stored, and only 

 slowly eliminated from the liver. Thus, the author found 

 zinc in the liver of a calf which had received 100 grammes of 

 zinc potassium chloride (equivalent to 42 grains of pure 

 zinc chloride) three weeks before death. One ounce of the 

 organ contained ^j^ grain of zinc ; there were traces in the 

 kidney and bile, but it was absent in the spleen. 



Toxie Doses. — Half an ounce of zinc sulphate daily for a 

 fortnight gave no marked effect on horses,* though larger 

 doses caused loss of appetite, nausea, and diuresis. 



In experiments with zinc potassium chloride the author 

 found that 100 grammes (nearly 4 ounces) caused illness, but 

 were not fatal to a young calf which had already received 

 several smaller doses. 



* Finlay Dun, " Veterinary Medicine," 1910, p. 239. 



