Some springs, as those of Bath, Matlock, and Buxton, owe their virtues rather to temperature than to any other cause, and others, as Malvern, to the diluent power of the water.
In the Codex Medicamentarius of Paris, formulæ are introduced for the preparation of several of the more distinguished mineral waters, under the head “Aquæ Minerales Arte Factæ.”[[392]]
ARGENTI NITRAS. L. Nitras Argenti. E.D.
Fused Nitrate of Silver, olim, Lunar Caustic.
Qualities. Fused nitrate of silver is in small cylinders of a dark grey colour, and presenting, when broken across, a crystalline structure. Odour, none; Taste, intensely bitter, austere and metallic; it tinges the skin indelibly black; when perfectly free from copper, it is not deliquescent. Chemical Composition; oxide of silver 70, nitric acid 30, or one atom of oxide and one atom of acid. Solubility. In an equal weight of water, at 60°; it is also soluble in alcohol. The solution readily yields transparent colourless crystals, the primary form of which is a right rhombic prism. Incompatible Substances. Fixed alkalies and alkaline earths, the muriatic, sulphuric, and tartaric acids, and all the salts which contain them; Soaps, arsenic, hydro-sulphurets, astringent vegetable infusions, undistilled waters. The solutions of nitrate of silver are not disturbed by ammonia, the ammoniuret being very soluble; the carbonate of ammonia, however, produces a precipitation. Nitrate of silver tinges the skin and hair black, and has been frequently employed for the latter purpose;[[394]] it likewise forms the basis of permanent ink.[[395]] Medicinal Uses. Tonic, antispasmodic, and escharotic; it is said to prove efficacious in epilepsy, but during a trial for several years in the Westminster hospital, I never could discover its virtues; many of the cases in which it has been supposed to have been successful, probably derived advantage from the purgative medicines which were simultaneously administered. It possesses a bitter taste, and it has been said to act like vegetable bitters upon the digestive organs, and to offer a resource in dyspeptic complaints. It is principally useful as an external application, and may be considered as the strongest and most manageable caustic that we possess;[[396]] whilst in solution it acts as a useful stimulant in indolent ulcers; and being possessed of the power of coagulating animal matter, it does not spread to any extent, and is therefore extremely convenient where a large eschar is to be avoided. A weak solution of this metallic salt has lately been strongly recommended by a French surgeon, as a remedy for piles of long standing; it also forms an excellent lotion to excite the weak granulations of fungous ulcers. It is, moreover, said to be highly useful as an injection in cases of puriform discharges from the ear; before we direct however such an application, it is highly necessary that we should ascertain the tympanum to be entire, or the liquid may escape into the internal ear, and occasion very alarming irritation; an event which unhappily occurred, not long since, in the case of a noble duke of high military renown. Forms of Exhibition. For internal use, in pills made with crumb of bread, with the addition of some sugar, to prevent the mass from being too hard. Dose, gr. 1/8, gradually increased to gr. j. Adulterations. Copper may be always suspected when it deliquesces, and is to be immediately detected by its solution assuming a blue colour, when supersaturated with ammonia. The sticks should be preserved in closely stopped phials, and covered with soft and dry paper. Antidote. When this substance has been taken in excess, muriate of soda is its true antidote; indeed, so completely does it decompose, and separate it from water, that if a saturated solution of nitrate of silver be filtered through common salt, it may be afterwards drunk with impunity. This circumstance alone, would of necessity render nitrate of silver a very uncertain remedy; and yet it is evident that the basis of this salt is occasionally absorbed, for there are several cases upon record, in which the oxyd of silver has been deposited in the rete mucosum, and given a purple hue of a very singular appearance to the patient; I have lately witnessed an instance of this kind in a lady who had taken large doses of the nitrate, for the purpose of curing a dyspeptic complaint; and several other similar cases stand recorded in different works.
ARMORACIÆ RADIX. L.E. (Cochlearia Armoracia )
Raphanus Rusticanus, D. Horse[[397]] Radish Root.
Qualities. Taste, hot and acrid; Odour, pungent. Chemical Composition. All its virtues depend upon an essential oil. Solubility. Both water and alcohol extract its active principles, but they are dissipated by decoction. Medicinal Uses. As a stimulant in paralysis it is often useful; Sydenham found it successful in dropsies which were consequent on intermittent fevers; Cullen recommends a syrup made with the infusion of horse radish, to remove that species of hoarseness which depends upon local relaxation; Dr. Withering extols an infusion of this root in milk as a cosmetic both safe and effectual. Incompatible Substances. Alkaline Carbonates; Oxy-muriate of Mercury; Nitrate of Silver; the Infusion of Galls and of Yellow Cinchona Bark, produce precipitates with the infusion of this root. Forms of Exhibition. In substance, scraped or swallowed whole, or in infusion.[[398]] Dose of the substance ʒj, of an infusion f℥ij. See Infus Armoraciæ comp. Officinal Preparations. Infusum Armoraciæ comp: L. Spiritus Armoraciæ comp: L.D.
ARSENICUM ALBUM. (Acidum Arseniosum.)
Oxydum Arsenici. E. Arsenicum. D. White Arsenic.