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 which shows that these fumes are not quite harmless. An apothecary's assistant, while preparing philosopher's wool, incautiously filled the whole laboratory with it. The same day he was seized with tightness in the chest, headache and giddiness; next morning with violent cough, vomiting, and stillness of the limbs; on the third day with a coppery taste in the mouth, some salivation, gripes, and such an increase of giddiness that he could not stand. He was then freely purged, after which a fever set in, ending in perspiration; and he got well in three weeks.

From these cases, and the experimental researches of Orfila, it is clear that the preparations of zinc, though not very active poisons, are nevertheless far from being innocuous. We are not acquainted with their effects when long and habitually introduced into the body in small quantities. About the time when physicians began to study with care the dangerous consequences of employing lead and copper in the manufacture of culinary vessels, it was conceived by some that zinc might prove a safe substitute. It was farther imagined by some military economists in France, that zinc might be profitably used instead of tinned iron in the manufacture of canteens and other articles of camp equipage, because the worn and damaged vessels would sell as old metal at little short of their original price, while tinned iron as old metal bears no value at all. But from the experiments of Deyeux and Vauquelin it subsequently appeared, that in the course of many culinary operations zinc is more liable to be attacked than either copper or lead;—that water left for some time in zinc vessels oxidates them, and acquires a metallic taste;—that if water acidulated with vinegar or lemon-juice is boiled in zinc, a solution is formed, in which the metal may be detected by its tests;—and that sea-salt, sal-ammoniac, and even butter, have the power of dissolving it also. Some singular inquiries were afterwards prosecuted by Devaux and Dejaer among the Spanish prisoners at Liége, with the view of proving, that frequent small quantities of zinc dissolved in the manner mentioned, and habitually taken with the food, have no injurious tendency; that even in large doses it can hardly be accounted poisonous, as it merely gives rise to vomiting and slight diarrhœa; and that an adulteration to such an amount would always betray itself by its strong disagreeable taste. These are certainly valuable facts, though not quite satisfactory. But it is unnecessary to inquire minutely into their validity; for, independently of all other considerations, vessels constructed of zinc are too brittle for domestic purposes. With regard to the effects of frequent small doses of sulphate of zinc, the only positive information I can communicate is, that I have often given medicinally from three to six grains thrice a day for two or three weeks, without observing any particular effect except in some persons sickness when the largest doses were taken; and others have frequently made the same observation. On the