Iron which has been acted upon by fire is spoiled, unless it is forged with the hammer. It is not in a fit state for being hammered when it is red-hot, nor, indeed, until it has begun to assume a white heat. By sprinkling vinegar or alum upon it, it acquires the appearance of copper. It is protected from rust by an application of ceruse, gypsum, and tar; a property of iron known by the Greeks as “antipathia.”[1688] Some pretend, too, that this may be ensured by the performance of certain religious ceremonies, and that there is in existence at the city of Zeugma,[1689] upon the Euphrates, an iron chain, by means of which Alexander the Great constructed a bridge across the river; the links of which that have been replaced are attacked with rust, while the original links are totally exempt from it.[1690] CHAP. 44.—SEVEN REMEDIES DERIVED FROM IRON. Iron is employed in medicine for other purposes besides that of making incisions. For if a circle is traced with iron, or a pointed weapon is carried three times round them, it will preserve both infant and adult from all noxious influences: if nails, too, that have been extracted from a tomb, are driven into the threshold of a door, they will prevent night-mare.[1691] A slight puncture with the point of a weapon, with which a man has been wounded, will relieve sudden pains, attended with stitches in the sides or chest. Some affections are cured by cauterization with red-hot iron, the bite of the mad dog more particularly; for even if the malady has been fully developed, and hydrophobia has made its appearance, the patient is instantly relieved on the wound being cauterized.[1692] Water in which iron has been plunged at a white heat, is useful, as a potion, in many diseases, dysentery[1693] more particularly. CHAP. 45.—FOURTEEN REMEDIES DERIVED FROM RUST. Rust itself, too, is classed among the remedial substances; for it was by means of it that Achilles cured Telephus, it is said, whether it was an iron weapon or a brazen one that he used for the purpose. So it is, however, that he is represented in paintings detaching the rust with his sword.[1694] The rust of iron is usually obtained for these purposes by scraping old nails with a piece of moistened iron. It has the effect of uniting wounds, and is possessed of certain desiccative and astringent properties. Applied in the form of a liniment, it is curative of alopecy. Mixed with wax and myrtle-oil, it is applied to granulations of the eyelids, and pustules in all parts of the body; with vinegar it is used for the cure of erysipelas; and, applied with lint, it is curative of itch, whitlows on the fingers, and hang-nails. Used as a pessary with wool, it arrests female discharges. Diluted in wine, and kneaded with myrrh, it is applied to recent wounds, and, with vinegar, to condylomatous swellings. Employed in the form of a liniment, it alleviates gout.[1695] CHAP. 46.—SEVENTEEN REMEDIES DERIVED FROM THE SCALES OF IRON. HYGREMPLASTRUM.