Part II.

Materia Medica.

133

but on being heJd some time in the mouth, it excites a veryviolent biting and burning ; which lasts a long time* and can-not be abated by washing out the mouth,

Ferkuji.Iron.

Lond. Dub. Ed.

This is the most common of all metals. It seems even tobe a constituent of organic substances, and'is the only metalwhich, when taken into the body, exerts no deleterious actionupon it. The numerous ores of iron which are found in everypart of the globe, may be reduced to the following genera.

1. Native iron. Immense isolated masses of this have beenfound in Siberia and in South America. Their origin is stillperfectly problematical.

2. Carburetted iron. Plumbago,

3. Sulphuretted iron. Pyrites.

4. Oxidized iron.

a. Protoxide. Magnetic iron ore; colour black or grey-

b. Peroxide. Not magnetic ; colour red or brown.

c. Carbonated.

d. Arseniated.

e. Tungstated.

The properties of iron, when obtained from any of theseores by the usual processes of fusion, &c. have been alreadydescribed. As its mechanical division is extremely difficult,it is directed to be kept in the shops in the state of filings orwire, and the scales of black oxide, which are found aroundthe smith's anvil. Soft malleable iron is the only kind fit forinternal use, as steel and cast-iron always contain impurities,and often arsenic.

Iron is prescribed,

I. In its metallic state.

Ferri limatura. Ed.

-------------------purificata. Ed.

Ferri ramenta et fila. Lond.Ferri scobs. Dub.

II. Oxidized.

1. Protoxide,

Ferri squamae. Ed.

Ferri oxydi squamae. Dub.

Oxidum ferri nigrum purificatum. Ed.

Oxydum ferri nigrum. Dub.

2. Peroxide,

Oxidum ferri rubrum. Ed. Dub.

3. Supercarbonated ; as in the chalybeate mineral waters.