COMMENTARY. It is not mentioned by Dioscorides, Pliny, Theophrastus, Aëtius, or any other ancient author but Galen and Paulus; nor has any one of the commentators noticed it. We are unable, therefore, to determine anything for certain respecting it. But as Dioscorides and Pliny ascribe nearly the same medicinal powers to the _Cacalia_ as our author does to the Cacanus, it seems not improbable that they may have been identical. Our author evidently borrows from Galen. Κάγκαμον, Cancamum; it is the tear of an Arabian wood, resembling myrrh, fragrant, and hence used in perfumes. It has the power of extenuating fat bodies, and is detergent and deobstruent. * * * * * COMMENTARY. Dioscorides treats of it in the portion of his work devoted to aromatics, calling it the tear of an Arabian wood, having some resemblance to myrrh, which was used in fumigations with myrrh and storax. He calls it emmenagogue; mentions that it is given in asthmatic, epileptic, and splenetic cases; says it is useful as a cleanser in diseases of the eye; but that it is most particularly applicable for fungous gums and toothache. (i, 23.) Galen has omitted it from his Mat. Med. Of the Arabians, Avicenna is the authority who has treated of it most distinctly. He calls it a gum of a bad taste which is brought from the region of the west. (This account of the country which produces it may warrant suspicion that he had confounded it with some other gum, the production of Italy or Spain.) He says of it, that some had confounded it with sandaracha (gum vernix?). In giving its medicinal virtues, he copies closely from Dioscorides (ii, 2, 382.) It is doubtful, from this imperfect description of the Cancamum, what substance it applies to; probably either to _Gum anime_ or to _Gum elemi_. There seems no good ground for referring it, as some have done, to _Lacca_; nor to some nondescript species of the _Amyris Katef_, as Sprengel does. (Ad Dioscor. l. c.) Καδμία, Cadmia, _Calamine_; both kinds of it are desiccant, but that which is called Botryitis, consists of the more subtile particles, and the Placitis, of the grosser. When calamine is burnt, it becomes desiccant and detergent, without pungency, and is also useful for sores requiring to be filled up, about the eyes and in the whole body, more particularly those on softer bodies, which are more humid, for those upon harder bodies require stronger means. * * * * *