The oxide of zinc has been credited with a special action on the nervous system, of tonic character in small, but depressant in large doses. Dr. Marcet traced drowsiness to its use, and others have recorded giddiness after taking it, and generally depressed nervous and mental conditions from the prolonged continuance of large doses (Medical Times, 1858; Medico-Chirurgical Review, ii., 1861). In cases of ultimate recovery from the effects of large doses of zinc salts there have been, besides the gastric symptoms, signs of impaired nerve-power, with perversion of taste and smell, tremor, or partial paralysis. Exposure to fumes of the molten metal, as in the course of certain metallic castings, gives rise to a curious train of symptoms, mainly nervous, and commonly known as "brass-founders' ague," and including general malaise, tightness of chest, a cold stage with rigors, followed by a hot stage with profuse sweating. These symptoms may recur periodically for several days (H. Greenhow, quoted Lancet, i., 1863 - v. p. 541).