552

ELEMENTS OE MATERIA MEDICA.

(c.) On man. —This salt acts locally as a powerful astringent, and,when employed in a concentrated form, as an irritant. The lattereffect depends on its chemical action on the organic constituents (albu-men, &c.) of the tissues. The remote effects of sulphate of iron areanalogous to those of other ferruginous compounds, and which have beenalready described.

Swallowed in small doses it has an astringent operation on the gastro-intestinal mucous membrane, and thereby diminishes the quantity offluids secreted or exhaled; hence its continued use causes constipation.It blackens the stools like other compounds of iron. It becomes ab-sorbed, and operates on the system as a tonic, stimulant, emmenagogue,and astringent. In large medicinal doses it readily excites pain, heat, orother uneasiness at the pit of the stomach, and not unfrequently nauseaand vomiting: this is especially the case in irritable conditions of thisviscus. In excessive doses it operates as an irritant poison. A girl took,as an emmenagogue, an ounce of it in beer, and was seized, in conse-quence, with colic pains, constant vomiting and purging for seven hours.Mucilaginous and oily drinks soon cured her (Cliristison, from Rust’sMagazin, xxi. 247).

Uses. —Sulphate of iron is to be preferred to other ferruginous com-pounds where there is great relaxation of the solid parts with immoderatedischarges. Where the long-continued use of ferruginous compounds isrequired, it is less adapted for administration than some other prepara-tions of iron, on account of its local action on the alimentary canal.

It is employed in lump, powder, or solution, as a styptic, to checkhaemorrhage from numerous small vessels. A solution of it is applied toulcerated surfaces, and to mucous membranes, to diminish profuse dis-charges; as in chronic ophthalmia, leucorrhcea, and gleet.

Internally it is administered in passive haemorrhages, on account of itssupposed astringent influence over the system generally: also in immo-derate secretion and exhalation; as in humid asthma, chronic mucouscatarrh, old dysenteric affections, colliquative sweating, diabetes, leucor-rhoea, gleet, &c. In intermittents it has been employed as a tonic. Ithas also been found serviceable against tape-worm. Its other uses arethe same as the ferruginous compounds generally ( vide p. 536).

Administration. —The dose of it is from one to five grains, in theform of pill. If given in solution the water should be recently boiled, toexpel the atmospheric air dissolved in it; the oxygen of which convertsthis salt into a persulphate. For local purposes, solutions of it are em-ployed of various strengths, according to circumstances. In chronicophthalmia we may use one or two grains to an ounce of water: as aninjection in gleet, from four to ten grains.

Fer'ri Car'bonas. — Car'donate of I’ron.

History. —This compound must not be confounded with the sesqui-oxide of iron, which is frequently termed carbonate of iron.

Natural History. —It occurs native in the crystallized state, consti-tuting the mineral called spathose iron. It is also found in most chaly-beate waters ( vide p. 145.)

Preparation. —It is prepared by adding a solution of an alkaline car-bonate to a solution of a protosalt (as the sulphate) of iron, the atmos-