COMMENTARY. We must refer to what we have stated in another work, which we have already often quoted, for the general literature of this subject. It will be sufficient in this place to state that the substance here treated of under the name of Cinnabaris is indisputably the _Sanguis Draconis_, or concrete juice of the _Dracœna Draco_. This is obvious from Dioscorides’s description of it, who says that it is of a deep colour, and hence some had thought it the blood of the dragon. (v, 109.) See further, Pliny (H. N. xxxiii, 38), and the very interesting note of Harduin, in which the origin of the confusion of the dragon’s blood with cinnabar is fully explained. Serapion treats of the _Sanguis Draconis_ as the production of a tree, and quotes a description of it from Dioscorides and Galen. What vegetable substance in their Mat. Med. Serapion refers to, we are at a loss to decide. One of his authorities, Constantinus, calls it the juice of a plant, possessed of styptic powers, and therefore used as an astringent both internally as a suppository, and externally when so applied. (De Simpl. 341.) Avicenna recommends it similarly, but gives no description of it. (ii, 2, 627.) It is to be borne in mind that besides the vegetable cinnabar, the ancients described two other substances under this name, viz., the native mineral cinnabar or sulphuret of quicksilver, and a factitious cinnabar, which was their Sal Atticum. See Hill (Mat. Med. 60), and Geoffroy (215.) The dragon’s blood is retained in the modern Greek Pharmacopœia, where it is set down as the product of the _Calamus Draco_. Κιννάμωνον, Cinnamomum, _Cinnamon_, is composed of extremely subtile parts, yet is not extremely heating, but only in the third degree. But of those in the same rank of calefacients none is so desiccative owing to the tenuity of its parts. The cinnamomis is a sort of weak cinnamon; but some call it pseudo-cinnamomum. * * * * *