COMMENTARY. The two species of elder, namely, the _Sambucus nigra_ and _Ebulus_, are much commended by the ancients for the cure of dropsy. As Dioscorides states, the elder is hydragogue, but disagrees with the stomach. He further recommends a hip-bath made of water in which elder has been boiled, for obstructions and hardness of the uterus (iv, 161.) Galen and the other Greek authorities treat of it in general terms like Paulus. The Arabians in treating of it generally borrow from Dioscorides and Galen. See particularly Serapion (c. 284.) It appears to be the _acte_ of Rhases (Cont. l. ult. i, 23); and is the _aktha_ of Ebn Baithar, according to his German translator, Dr. Sontheimer, in which opinion we fully agree with him. The Sambucus of Avicenna (ii, 2, 611) is not the elder, but the jasmine. We have not been able to detect the other in his Book on the Mat. Med., but can scarcely suppose that he has entirely overlooked it. Ἅλες, Sales, _Salts_, have desiccant and astringent powers. Wherefore they consume whatever humours are in the body, and also contract by their astringency. Whence they form pickles, and preserve substances from putrefaction. Roasted salts are more discutient. * * * * * COMMENTARY. For an account of the factitious salts of the ancients, see in particular Pliny (H. N. xxxi, 39.) Sprengel remarks that the ἅλος ἄχνη, or _spuma maris_, is merely the skum or down of salt, which sticks to rocks in such situations as salt is usually formed in. The ἅλος ἂνθος, or _flos salis_, he adds, is a very different substance, being a native, impure carbonate of soda; containing also magnesia, lime, and some terrene admixture, to which it owes its colour. When deprived of its carbonic acid it becomes caustic, and was then called ἄφρος νίτρου by the ancients (v. ἀφρόνιτρον.) The _sal ammoniac_ of the Greeks was a native fossil salt, and considerably different from ours. Geoffroy seems to agree with Salmasius, that it was the _sal gem_. Dr. Hill also maintains that it was only a peculiar form of the sal gem. See also Jameson’s ‘Mineral.’ (iii, 15.) In fact, from Dioscorides’ description of the ammoniac salt, nobody can avoid seeing that it was merely a variety of the common fossil salt. He treats of the medicinal faculties of the salts at so great length that we dare not venture to copy his account of them. It is literally translated by Pliny (xxxi, 45.) He recommends them internally by the mouth and in clysters, and externally in fomentations, baths, and fumigations. Serapion quotes the whole of Dioscorides’ chapter on Salts without supplying much additional information of his own. He describes minutely the process of roasting salts in an earthen vessel, and covering them up with coals, and thus applying heat to them. The _sal ammoniac_ he describes, from Arabian authorities, as being a white red salt, extracted from hard clear stones, and being saltish, with much pungency (c.