COMMENTARY. Our author manifestly copies from Galen; and whoever will carefully compare his account of it with Dioscorides’s chapter on Rhâ, cannot fail to come to the conclusion that both apply to the same substance, namely, the _Rheum Rhaponticum_. We therefore shall confine our attention in this place to it, reserving to the Appendix what we have got to say on the knowledge possessed by the ancients of the purgative rhubarb. Dioscorides says of it, that its prevailing power is astringency, with a certain degree of heat; and he recommends it to be taken in a draught for flatulence of the stomach, atony, all kinds of pain, spasms, diseases of the spleen, liver, and kidneys, tormina, affections of the chest and bladder, distension of the hypochondria, diseases of the uterus, sciatica, hæmoptysis, asthma, hiccough, dysentery, cæliac affections, intermittents, and the bites of venomous animals; also for lividity and leprosy when rubbed in with vinegar, and for discussing all chronic inflammations in a fomentation. (iii, 2.) Galen’s account of it, as already stated, is exactly the same as our author’s. Oribasius evidently takes his description of it from Dioscorides; and Aëtius, like our author, as clearly abridges Galen. There is no mention of the _Rhâ_ in the works either of Hippocrates or of Celsus. Pliny’s description of it (he calls it _Rhacoma_) is manifestly imitated from Dioscorides. (H. N. xxvii, 105.) As already stated, we shall reserve our exposition of the views of the Arabians to the Appendix. Ῥητίναι, Resinæ, _Resins_, are all calefacient and desiccative; but the turpentine holds the first place, being discutient, emollient, and attenuating, and also detergent, whereby it cures itch; and that of larch is like to it. The resin of the pitch-tree, and still more that of the wild pine, are more acrid, but neither more discutient nor attractive. Those of the pine and fir hold an intermediate place. * * * * *