part in. Metallic Preparations. — Iron.

G63

Syn. Tartrate de Per et de Potasse (F.), Eissenweinstein (I.), Tavtrato <liPotassa e di Ossido di Ferro (G.)-

Of these three processes, that of the Dublin college is tobe preferred, as it affords a perfect triple salt,- whereas muchof the iron employed in the London and the Edinburgh pro-cesses remains unaltered, or is at least only in the form of asimple oxide. In the London process, the iron is first oxi-dized by the partial decomposition of the water, aided by theaction of the air, and the oxide thus formed unites with thesuperabundant acid of the supertartrate of potass: hence thedried mass consists of tartrate of potass and of iron, mixed withoxide of iron, and some metallic iron. The subsequent addi-tion of water, and re-exposure to the air, are intended torender the oxidizement complete, and convert the whole tothe state of the triple salt; but as this is not effected, it is pro-bable that the proportion of supertartrate of potass ordered, isinsufficient for the large quantity of the metal directed tobe used. In the Dublin process, the superabundant acidof the supertartrate of potass dissolves as much of the oxideof the carbonate of iron as it can take up; and a clearsolution is obtained, which, by evaporation, yields a truetartrate of potass and of iron. As it is almost impossible toprocure this salt in crystals, die solution may be evaporated todryness.

Qualities. — Tartrate of potass and of iron is inodorous, liasa slightly styptic taste, and is of a brownish green colour. It isvery soluble in water; and deliquesces, in some degree, whenexposed to the air, so as to require to be kept in closely stop-ped phials. The cold solution of the alkalies and their sub-carbonates do not decompose this salt; but it is instantly de-composed when boiled with any one of them except ammoniaand its subcarbonate, which in neither state affect it. Thestrong acids, lime-water, hydro-sulphuret of potass and infu-sions of astringent vegetables decompose it, and are thereforeincompatible in formulas with it.

Medical properties and tises. — This salt possesses the samemedicinal powers as the other preparations of iron; but fromits mildness, slight taste, and ready solubility, it is a moreconvenient form tor the administration of iron to children, andin many cases in which the other saline preparations of itprove nauseating, and sit uneasy on the stomach. It is ad-vantageously given in all the cases in which chalybeates proveuseful: and is also extolled as a remedy in dropsy, in which itis supposed to exert both a diuretic and a tonic power. Thedose is from grs. x. to 5 ss., given either in a state of solution,or in the form of powder or bolus, combined with an aromatic,or a bitter.

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