CARBONATE OF ZINC. 679
Physiological Effects. —Its effects are analogous to those of the sulphate ofzinc. Its local action is astringent, Taken internally, in small doses, it acts asa tonic and antispasmodic; large doses occasion vomiting and purging. Deveauxand Deiaer (Orfila, Toxicol. Gen.) deny that it is a poison, even in large doses.
U SES . __It is rarely administeied internally; bin is applicable as an emetic,
tonic and antispasmodic, in the same cases in which the oxide or sulphate ofzinc is employed.
As a topical reraedy, it is used on account of its astringent qualities in chronicOphthalmia, gleet, and leucorrhoea. In the latter stages of gonorrhoea I havefound it far more successful than the sulphate. Its beneficial effects were firstdescribed by the late Dr. Wm. Henry, of Manchester. (Lond. Med and P/iys.Journ. ix. 53. 1803.) Sir A. Cooper {Landet, iii. 199.) recommends, as thebest injection which can be used in the third week of gonorrhoea, a mixture ofsix orains of sulphate of zinc and four ounces of liquor plumbi subacetatis dilutus.Of course double decomposition takes place, and the active ingredient is the ace-tate of zinc. .
Administration. —When exhibited internally, as a tonic or antispasmodic, thedose is one or two grains gradually increased. As an emetic it is rarely admi-nistered: the dose is from ten grains to a scruple: its Operation is very safe.^ Asa lotion or injection, it is employed in the form of aqueous Solution, containingtwo or more grains of the salt to an ounce of water.
ZINCI ACETATIS TINCTURA, D, (Sulphate of Zinc; Acetate of Potash, ää onepart. Triturate them together, and add sixteen parts of Rectified Spirit; mace-rate for a week with occasional agitation, and filter through paper.)—Here wehave double decomposition: sulphate of potash and acetate of zinc are formed.The first is precipitated, being insoluble in spirit, the second remains in Solution.One drachm contains a quantity of acetate of zinc equal to about four grains ofthe crystallized acetate. When diluted with water it is used as a collyrium andinjection.
G. ZIN'CI CAR'BONAS.—CARBONATE OF ZINC.
(Calamina; Carbonas Zinci impura, L. —Calamina praparata; Lovigated impure Garbonate ofZinc, E. —Carbonas Zinci impuruni; Calamina, D.)
History. __The native carbonate of zinc was perhaps known to the ancients,
thoush they were unacquainted with its nature. The term Calamine is appliedboth to the native carbonate and native Silicate of zinc: the latter is termed byway öf distinction Electric Calamine.
Natural History. —Native carbonate of zinc (Calamine) is found in greatabundance in several parts of England, (in the counties of Somerset, Derby,Durham, &c.,) as well as in various parts of the continent of Europe (in Carin-thia, Hungary, Silesia, &e.) It occurs crystallized or in compact or earthymasses. Its colour varies, being more or less gray, yellow, or brown. Its sp.gr. is 4-2 to 4-5.
Preparation. —Calamine ( Calamina) or the impure carbonate of zinc (Car-bonas Zinci impura,) is directed to be calcined, in order to make it pulverizable.But in this process water and more or less of the carbonic acid is expelled. It isthen reduced to a very fine powder (usually in mills,) and is afterwards submittedto the process of elutriation. By this means we obtain Prepared Calamine [Cala-mina Prceparata, L. E.; Zinci Carbonas impurum prceparatum, D.)
Properties. __Prepared calamine is met with in the shops in the form of a heavy
pinkish or flesh-coloured powder, or made up into little masses. When pure, itdissolves in nitric, hydrochloric, or sulphuric acid, with effervescence. Variousimpurities mixed with calamine are insoluble in these acids.
Characteristics. —The effervescence with the mineral acids shows calamine tobe a carbonate. The presence of zinc in the Solution is determined by ths tests