ZIN

51'

tier and urinary organs, and, it would seem, without any theory respect-ing its modus operandi ; but it has at length fallen into disrepute, and pro-bably with justice : it occasionally renders the urine of a blackish colour,a fact which is not easily to be explained. When it is administered, theform of powder is preferred, and in doses from 9j to 3j. The leaves ofthe Vaccinium Vitis Idcea(Red Whortle-Berry,) are sometimes substitut-ed for those of Uva Ursi; but they may be easily distinguished ; botani-cally, by the net work appearance of their veins above, and by their dotsunderneath ; chemically, by their infusion neither precipitating the solu-tion of isinglass, nor that of sulphate of iron.

ZINCI OXYDUM. L.E.D.

Oxide of Zinc.

This is occasionally used internally as a tonic, and may be exhibited inthe form of pill. It is however principally employed externally, as amild but efficient astringent ; viz. Ung • Zinci. Adulterations. Dr.Koloff of Magdeburgh has lately discovered the casual presence of Ar-senic* in this oxide ; by boiling the substance in distilled water, and as-saying the solution with the ammoniaco-nitrate of silver, its presence maybe instantly recognised; Chalk may be detected by sulphuric acid, excit-ing an effervescence ; and White Lead, by its forming an insoluble sul-phate of lead. It ought to be volatile.

ZINCI SULPHAS. L.E.D.

Sulphate of Zinc, olim, White Vitriol.

Qualities. Form, crystals, which are four-sided prisms, terminatedby four-sided pyramids ; they are slightly efflorescent; Taste, styptic, me-tallic, and slightly acidulous. Chemical Composition. One proportion-al of oxide, and one proportional of acid ; its crystals contain seven pro-portionals of water. Solubility. It is soluble in 2.5 times its weight ofwater at 60°, and in less than its own weight of boiling water, but is quiteinsoluble in alcohol. Incompatible Substances. Alkalies: earths; hy-dro-sulphurets ; astringent vegetable infusions; Milk. Med. Uses. Tonic,astringent, and, in large doses emetic, (Form. 66.) As an emetic it ope-rates directly, and offers therefore a prompt resource in cases of poison,or where an immediate discharge from the stomach is required ; it ap-pears to differ from most remedies of this nature, in not proving diapho-retic in smaller doses : in spasmodic! coughs it is administered with thebest effects, especially when combined with camphor or myrrh, [Form.59 :) in affections of the chest attended with inordinate secretion, Ihave witnessed much benefit from its exhibition, particularly whenpresented in the form of lozenge ; and, when dissolved in water,in the proportion of grs. ij to fjj, it forms a useful injection in fluor

* I have been lately informed by a practical chemist, that he has occasionally foundhis hydrogen, when produced by zinc and dilute acid, to contain a portion of Arsenu-reted hydrogen; a fact -which confirms the assertion of R,olofl'.

t The various quack remedies advertised for the cure of the hooping cough areeither Opiates, or Medicines composed of sulphate of zinc. The nostrum, sold un der'.he name of Anti-per-tussis, contains this metallic salt as its principal ingredieut