Pliny the Elder, Natural History 34.151
“There are other medicinal applications of iron beyond surgery. For when a circle is drawn around both adults and infants—or of they carry a sharp iron weapon with them—it is useful against poisonous drugs. Iron nails which have been taken out of tombs are useful protections against nightmares if they are hammered down before a threshold.
A small penetration with an iron weapon which has wounded a man is effective against sudden side and chest pains. Some afflictions are treated by cauterization, especially true for the bite of a rabid dog, since even when the disease has advanced and those afflicted are starting to exhibit fear of water, they experience relief at cauterization. The drinking of water which has been heated with burning iron is good for many symptoms, but especially for dysentery.”
XLIV. Medicina e ferro est et alia quam secandi. namque et circumscribi circulo terve circumlato mucrone et adultis et infantibus prodest contra noxia medicamenta, et praefixisse in limine evulsos sepulchris clavos adversus nocturnas lymphationes, pungique leviter mucrone, quo percussus homo sit, contra dolores laterum pectorumque subitos, qui punctionem adferant. quaedam ustione sanantur, privatim vero canis rabidi morsus, quippe etiam praevalente morbo expaventesque potum usta plaga ilico liberantur. calfit etiam ferro candente potus in multis vitiis, privatim vero dysentericis.