On Medicine (De Medicina), Vol. 2

thyme oil, pitch and turpentine. The phenol or carbolic acid derived from gas tar and used by Lister as an antiseptic was akin to the thymol derived from thyme flowers, though the latter was weaker in its action. The antiseptic which largely replaced phenol in surgical practice was mercuric chloride. Celsus frequently recommends orpiment and sandarach, the arsenic sulphides, for cleaning wounds and ulcerations, but as antiseptics these are much weaker than the mercury chloride. Salt solution, so largely used in the great war in the treatment of wounds, was used in ancient medicine for the same purpose, that of prompting a thin discharge, and is often mentioned by Celsus.ᵃ

HOMOEOPATHIC AND RUSTIC OR POPULAR REMEDIES

Throughout history a knowledge of herbs and drugs and their medicinal uses has been connected with the early systems of philosophy and occult lore. The "doctrine of signatures" expressed the popular belief that certain plants and minerals bore symbolical marks which indicated the diseases which nature intended them to cure, or that their outward appearance corresponded with the bodily condition of the patient.ᵇ Traces of this theory and of a belief in sympathetic magic are to be found in many of the remedies, especially the rustic or popular remedies, mentioned by Celsus. A sympathy or "homoeopathy"

ᵃ See list s.v. sal. under the word salt. A split fig, which he mentions as a common application on wounds (vol. II., pp. 159, 161, 289) was used for the same reason, as the sugar in the pulp would promote a thin discharge.
ᵇ For an account of the "doctrine of signatures" cf. T. J. Pettigrew, Superstitions connected with Medicine or Surgery, 1844.