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ELEMENTS OF MATERIA MEDICA.

alum, it is to be recollected that the vegetable astringents decompose it;by which the astringent property of the mixture is probably di-minished.

For topical uses, alum is used in the form of powder, solution, andpoultice. The powder of burnt alum is sprinkled over ulcers, to destroyspongy granulations. Powder of crystallized alum is applied to themouth and throat as before mentioned. Solutions of alum are made, fortopical purposes, of various strengths, according to the object in view.

The Cataplasm a Aluminis, Ph . Dub. ( Alum curd ofRiverius, Albu-men Aluminosum) is prepared by shaking the whites of two eggs with adraclim of alum. “ In cases of chronic and purulent ophthalmia, it isapplied to the eye between two folds of old linen. It has been praisedas a good application to chilblains which are not broken” (Barker andMontgomery’s Observations on the Dub. Pharm.)

The Liquor A lu min is Compositus, Ph . L. (Aqua aluminosa Ba-teana, or Bates's alum water) consists of alum, sulphate of zinc—each anounce; boiling water, three pints: dissolve and strain.. It is used as a deter-gent and astringent wash in old ulcers ; when diluted, as a collyrium inmild conjunctival inllammation, as an injection in gleet and leucorrhcea,and as an application to chilblains and slight excoriations.

Antidote. —In a case of poisoning by alum, let the contents of thestomach be immediately evacuated. Promote vomiting by the use oftepid diluents. The inflammatory symptoms are to be combated by theusual antiphlogistic means. Magnesia has been employed, but is saidby Devergie to be altogether useless.

Order 16 . Compounds of Arsenicum .

Ac’idum Arsenic! sum. — Arse'nious Ad id.

History. —Arsenious acid, commonly termed white arsenic (arsenicumalbum) or oxide of arsenic, is first distinctly mentioned by Geber ( Invent.of Verity, cli. vii.), who seems to have been also acquainted with metallicarsenic ( Sum of Perfection, book i. part iv. ch. ii.) Hippocrates (DeUlceribus ) employed apptvucov {orpiment or sesquisulphuret of arsenicum)and aavSapaKt] {realyar or sulphuret of arsenicum) as topical remedies.Dioscorides (lib. v., cap. xxi.) is the first author who uses the word apatvu;by{orpiment).

Natural History. —Arsenious acid occurs only in the mineral king-dom. It is rather a rare mineral, and is found at Andreasberg , in theIlartz; at Joachimsthal, in Bohemia ; and at some few other places.

Preparation. —It is prepared in Silesia, Bohemia, Saxony , andCornwall.

At Altenberg it is obtained from arsenical iron ( Mispickel ), a compoundof arsenicum, iron, and sulphur. After being reduced to powder the oreis roasted in a muffle furnace (fig. 56), by which the arsenicum is con-verted into arsenious acid. This is conveyed in the state of vapour,called flowers of arsenic or smeltinghouse-smoke {Huttenrauch), into thecondensing chamber (fig. 57), where it is deposited in a pulverent form,and in this state is called rough arsenious acid, or poison-flour {Giftmehl).

The rough arsenious acid is refined by sublimation. This is effectedin cast-iron pots, as shewn in fig. 58, p. 376, to which cylindrical iron