SULPHATE OF IRON.

705

The Common Green Vitriol, or Copperas of the shops, is a mixture of the sul-phates of the protoxide and sesquioxide of iron. It sometimes contains copper,which may be recognised by immersing a clean iron spatula in a Solution of it; theiron becomes encrusted with copper: or it may be detected by adding excess ofcaustic ammonia, and filtering the liquor. If copper be present, the liquor willhave an azure blue tint. The ammoniacal liquid should yield, by evaporation, nofixed residuum.

Physiological Effects, a.. On Vegetables. —Sir H. Davy (Jlgricult. Chan.4th ed. 186.) ascribes the sterility of a soil to the presence of sulphate of iron.

ß. On Jinimals. —C. G. Gmelin (Vers. u. d. Wirk. &c. 84.) found that twodrachms of sulphate of iron given to a dog caused vomiting only; that forty grainshad no effect on a rabbit; and that tw'enty grains, thrown into the jugular vein ofa dog, produced no effect. Dr. Smith, (Q,uoted by Wibmer and by Christison.)however, found that two drachms proved fatal to a dog when taken into the sto-mach or applied toa wound. Orfila (Toxicol. Gen.) obtained similar results. Theeffects were local inflammation and a specific affection of the stomach and rectum.According to Weinhold, (Q,uoted by Richter, Ausf. Arzneiin. v. 55.) the spieenof animals fed with it becomes rcmarkably small and compact.

y. On Man. —This salt acts locally as a powerful astringent, and, when em-ployed in a concentrated form, as an irritant. The latter effect depends on itschemical action on the organic constituents (albumen, &c.) of the tissües. Theremote effects of sulphate of iron are analogous to those of other ferruginous Com-pounds, and which have been already described.

Swallowed in small doses it has an astringent Operation on the gastro-intestinalmucous membrane, and thereby diminishes the quantity of fluids secreted or ex-haled: hence its continued use causes constipation. It blackens the stools likeother Compounds of iron. It becomes absorbed, and opsrates on the System as atonic, stimulant, emmenagogue, and astringent. In large medicinal doses it readilyexcites pain, heat, or other uneasiness at the pit of the stomach, and not unfre-quently causes nausea and vomiting: this is especially the case in irritable condi-tions of this viscus. In excessive doses it operates as an irritant poison. A girltook, as an emmenagogue, an ounc'e of it in beer, and was seized, in consequence,with colic pains, constant vomiting and purging for seven hours. Mucilaginousand oily drinks soon cured her. (Christison, from Rust's Magazin, xxi. 247.)

Uses. —Sulphate of iron is to be preferred to other ferruginous Compounds wherethere is great relaxation of the solid parts with immoderate discharges. Wherethe long continued use of ferruginous Compounds is required, it is less adapted foradministration than some other preparations of iron, on aecount of its local actionon the alimentary canal.

It is employed in lump, powder, or Solution, as a styptic, to check hemorrhagefrom numerous small vessels. A Solution of it is applied to ulcerated surfaces, andto mucous membranes, to diminish profuse discharges ; as in chronic Ophthalmia,leueorrheea, and gleet.

Internally it isadministered in passive hemorrhages, on aecount of its supposedastringent influence over the system generally: also in immoderate secretion andexhalation ; as in humid asthma, chronic mucous catarrh, old dysenteric affections,colliquative sweating, diabetes, leucorrhcea, gleet, &c. In intermittents it hasbeen employed as a tonic. It has also been found serviceable against tape-worm.Its other uses are the same as the ferruginous Compounds before mentioned.

Administration. —The dose of it is from one to five grains, in the formof apill. If given in Solution the water should be recently boiled, to expel the atmos-pheric air dissolved in it; the oxygen of which converts this salt into a persul-phate. For local purposes, Solutions of it are employed of various strengths, ac-cording to circumstahees. In chronic Ophthalmia we may use one or two grainsto an ounce of water: as an injeetion in eleet, from four to ten grains.

1. FERRI SULPIIAS BX8ICCATU», E. ; Dricd Sidphats of Iron. —(Expose any

Vol. I.— 89