This metal first became officinal in the present edition of the U. S. Pharmacopoeia, having been introduced into the primary catalogue of that work, as the source of sulphate of cadmium. Cadmium is a white metal, malleable and ductile, cracking like tin when bent, fusible at 440°, vola-tilizable, and of the sp. gr. 8.7. it appears to resemble zinc more closely in its medical relations than any of the other officinal metals. its preparations are said to be poisonous in over-doses; and several cases are on record in which alarming symptoms were produced by inhaling the powdered carbonate; the most prominent being vomiting and purging, constriction of the throat, embarrassed respiration, giddiness, and tetanic spasms. The only officinal preparation is the sulphate; but the iodide has also been used.