COMMENTARY. The squama æris was a black per-oxyd of copper. The squama ferri, a black oxyd of iron. The stomoma was the chalybs or steel. See Dioscorides (v, 89), with the Commentaries of Matthiolus and Sprengel, and also the Appendix to Dunbar’s Lexicon. Geoffroy says of the squama æris, that it is little different from the æs astum being only the particles of burnt copper that fly off when hammered. Dioscorides calls it astringent and epulotic: when drunk with honeyed water, he says, it is phlegmagogue; some give it in flour as a pill; it is mixed, he adds, with ophthalmic remedies, drying defluxions, and removing asperities of the eyelids. The stomoma, he says, is inferior to the squama æris as a purgative. (v, 89, 90.) Our author’s account of these substances is borrowed from Galen. Aëtius also copies from Galen. Oribasius gives a fuller description of them, differing very little from that of Dioscorides. The Arabians treat of all these substances, as usual, borrowing freely from Dioscorides, and not adding much of their own. See in particular Avicenna (ii, 2, 231); Serapion (c. 404); Rhases (Cont. l. ult. vi, 48); Averrhoes (Collig. v, 43.) They prescribe the squama æris internally as a purge, and say of it that when the palate is smeared with it vomiting is excited. These substances occur in the Hippocratic treatises and in the works of Celsus. They have not been used medicinally in this country for some time past. The Hindoos use the preparations of copper both internally and externally, according to Dr. Royle. (Hindoo Med. 90.) Λευκάκανθον, Leucacanthon, _White Acanthus_ (called also Polygonaton and Ischias); its root is of a cutting nature and desiccative in the third degree, and it is heating in the first. * * * * * COMMENTARY. We can only determine for certain that it belonged to the _Carduineæ_, but can scarcely venture to fix the genus, so loose is the description which the ancient authors have given of it, and so various the conjectures of modern commentators and herbalists respecting it. Upon the whole, the preponderance of the authorities is in favour of the _Cirsium tuberosum_. Dioscorides says of it, that its root is intensely bitter, and that the decoction of it with wine relieves chronic pleurisy and sciatica, ruptures and sprains, and further, that it relieves toothache. (iii, 19.) Galen recommends it in cæliac and stomach affections and hemoptysis; as a cataplasm to swellings, and a cure to toothache when used as a gargle. Aëtius gives the same character of it. The Arabians ascribe the same virtues to it, and also hold it to he alexipharmic. See in particular Avicenna (ii, 2, 80, 671) and Rhases (Cont. l. ult. i, 118.) The use of it in medicine is as old as the Hippocratic age. See Dierbach’s Materia Medica Hippocr. Λευκὰς, Leucas, is heating and desiccative in the third degree, but its prevailing property is acrimony. * * * * *