706

ELEMENTS OF MATERIA MED1CA.

convenient quantity of Sulphate of Iron to a moderate heat in a procelain orearthenware vessel, not glazed with lead, tili it is converted into a dry grayish whitemass, which is to be reduced to powder.)—By exposure to a moderate heat thecrystals lese fths of their water by crystallization; so that 85 grains of dried sul-phate are equfvalent to 139 grs, of the crystallized sulphate; or 3 grains are equalto 4 T a 0 gra of the crystals. The dried sulphate is used in the following prepara-tion.

I fUMM FERRI STJLPHATIS, E.; Pills of Sulphate of Iron.— (Dried sulphate ofIron, two parts; Extract of Taraxacum, five parts; Conserve of Red Roses, twoparls; Liquorice-root powder, three parts. Beat them together into a proper mass,which is to be divided into five-grain puls.)—Each pill should contain f of a grainof dried sulphate of iron.—Dose, one to three pills.

12. EER'RI CAR'ßONAS.—CARBONATE OF IRON.

History. —This Compound must not be confounded with the sesquioxide ofiron, which is frequently but improperly termed carbonate of iron (see p. 687.)

Natural History. —It occurs native in the crystallized state, constituting themineral called Spathose Iron. It is also found in the carbonated chalyheute waters(see p. 248.)

Preparation. —It is prepared by adding a Solution of an alkaline carbonate toa Solution of a protosalt (as the.sulphate) of iron, the atmospheric air being care-fully excluded. The carbonate of the protoxide of iron is precipitated. Whenwe atteinpt to collect and dry it, decomposition takes place; oxygen of the air isabsorbed, carbonic acid escapes, and sesquioxide of iron remains (see Ferri &s-quioxyditm, p. 687.) Hence when employed in medicine it must be preparedextemporaneously.

Properties. —Native protocarbonate of iron is yellow: the primary form of itscrystals is the obtuse rhombohedron. Carbonate of iron prepared as abovedirected is a white precipitate, which by exposure to the air becomes at firstgreenish, then brown [sesquioxide.') It is insoluble in water, but dissolves insulphuric or hydrochloric acid with effervescence. It also readily dissolves incarbonic acid water: the acidulo-chalybeale waters are natural Solutions of thiskind (see pp. 248 and 250.)

Characteristics. —It dissolves in diluted sulphuric acid with effervescence.The Solution possesses the before-mentioned properties of the ferruginous Solu-tions (see p. 682.)

Composition. —Carbonate of the protoxide of iron is thus composed:—

Protoxide of Iron ....

Jiloras.___ 1 ....

Eq. m.

.... 36 ....

°2

Per Cent..... 62.... 33 ......

Stromeyer

.. 59-6276.. 38-0352

.... 58 ....

... 100 ......

.. 97-6628

Physiological Effects and Uses. —It is one of the most valuable of the ferru-ginous Compounds, on accountof the facility with which it dissolves in the fluidsof the stomach, and becomes absorbed. Its local efl'ects are very mild.

Its uses are those of chalybeates in general, and whieh have been before men-tioned.

1. FERRI CARBONAS SACCHARATUM, E, Saccharihe Carbonate of Iron. (Sul-phate of Iron, 3iv.; Carbonate of Soda, 3v.; Pure Sugar, 3ij.; "Water, Oiv. Dis-solve the sulphate and carbonate each in two pints of the water; add the Solu-tions and mix them; collect the precipitate on a cloth filter, and immediatelywash it with cold water, squeeze out as much of the water as possible, and with-out delay triturate the pulp which remains with the sugar previously in fine