658

Metallic Preparations. — Iron.

part III.

portions must necessarily vary from variations in the conductof the process.

Qualities. — It is inodorous, has a styptic taste, and a red-dish-brown colour; dissolves in acids with effervescence ; andis decomposed by heat.

Medical properties and uses. — The rust of iron is tonic andemmenagogue. Next to the black oxide it is the least active ofthe preparations of this metal. It has lately been recom-mended with much confidence, both as an internal remedy,and an external application in cancer ': and is perhaps one ofthe best remedies that has yet been tried in tic douloureux. Ihave had an opportunity of trying its powers in two wellmarked cases of this disease; in both of which it proved suc-cessful : but its use required to be long persisted in, as thedisease returned in both instances, when its use was too soondiscontinued. In large doses it often occasions uneasiness atthe stomach; yet Cullen says, " We have always found thesimple rust as effectual as any other preparation; and the sto-mach bears it better than any 2 other." It is given in the formof pills, combined with aromatics and bitter extracts. Thedose is from grs. iv. to 3 j. given twice a day.Officinal preparation. Tinctura Muriatis Ferri, D.FERRI SUBCARBONAS, Lond. Subcarbonate of? Imn."Take of sulphate of iron, eight ounces ,■ subcarbonate ofsoda, six ounces ,■ boiling water, a gallon. Dissolve separatelythe sulphate of iron and the subcarbonate of soda in eight pintsof water, then mix together the solutions, and set the mixtureaside, that the powder may subside; then pour off the super-natant fluid, wash the sub-carbonate of iron in hot water, anddry it, wrapped up in bibulous paper, with a gentle heat."

Carbonas Ferri pr^cipitatus, Edin, Precipitated Car-bonate of Iron. Carbonas Ferri, Dub. Carbonate, of Iron." Take of sulphate of iron, four ounces; subcarbonate ofsoda, fve ounces ; water, ten pounds. Dissolve the sulphate inthe water : then add the subcarbonate previously dissolved inthe water, and mix them together. Let the carbonate of iron,which is precipitated, be washed with tepid water, and after-wards dried."

This preparation is also a subcarbonate of iron. By mixingthe solutions together, a double decomposition is effected; the

1 Carmichad on the Use of Carbonate of Iron in Cancer.

2 Tt is the carbonate of iron "which is contained in chalybeate waters, held insolution by the excess of carbonic acid. By exposing these waters to the air, thecarbonic acid flies oft', oxygen is attracted, and the carbonate falls down in theform of a yellowish sediment.

3 Chalybs praparatus & aceto, et sine aceto, P. L. 1720. Chalybis rubigo prtepa.rata, P. L. 1745. Ferri rubigo, P. L. 1787.