Sub-murias Hydrargyri sublimatum. D.
Sub-murias Hydrargyri Mitis. E.
vulgo. Calomel.[[529]]
This preparation has been known in pharmacy for upwards of two centuries under a variety of fanciful names, such as Draco mitigatus; Aquila alba; Aquila mitigata; Manna metallorum; Panchymagogum minerale; Panchymagogus quercetanus; Sublimatum dulce; Mercurius dulcis sublimatus; Calomelas; and yet there is not a name in this list that is so objectionable as the one at present adopted by our colleges: for whether we adhere to the theory of muriatic acid being the simple body, or accede to the new views of chlorine, the name is equally inappropriate; if we regard it as a compound of muriatic acid and oxyd of mercury, it is not a sub-muriate, but as much a muriate as the corrosive sublimate; the only difference depending upon the degree of oxidizement of the mercury, which is at a minimum in calomel, and at a maximum in sublimate. According to the new views respecting chlorine, calomel must consist of one proportional of chlorine with one proportional of metal, and is therefore a chloride of mercury. (“Proto-chloruretum Hydrargyri.” Codex Med. Paris.)
Qualities. Form. A semi-transparent mass, consisting of short prismatic crystals;[[530]] inodorous, insipid, and of an ivory colour, which deepens by exposure to light. Solubility. It is considered as being insoluble, since according to Rouelle, one part requires 1152 of water, at 212° for its solution. Incompatible Substances. Alkalies and lime water decompose it and turn it black, in consequence of precipitating the black oxyd of the metal; it is also decomposed by soaps, sulphurets of potass and antimony; and by iron, lead, and copper; hence it is improper to employ any metallic mortar for dispensing medicines which contain it. There seems to be reason for supposing that this preparation may undergo decomposition in transitu, and that therefore some substances may be chemically, and yet not be medicinally incompatible with it. If calomel be boiled for a few minutes in distilled water to which alcoholized potass has been added, it is completely decomposed, a muriate of potass and black oxyd of mercury being the new products. Calomel is not affected by sulphuric acid in the cold, but, at a boiling temperature, corrosive sublimate, and deuto-sulphate of mercury are formed. Medicinal Uses.[[531]] This mercurial preparation is more extensively and more usefully employed than almost any other article of the materia medica. It is capable of curing syphilis in every form, provided it does not run off by the bowels; and in obstructions and hepatic affections, it is in well-regulated doses a most valuable remedy; in combination, it probably merits the appellation of Dirigens, more decidedly than any other remedy with which we are acquainted, for when combined with certain diuretics, it is diuretic, (Form. 103, 104) and in diaphoretic arrangements, it is diaphoretic: it moreover imparts force to many of the mild, and moderates the severity of drastic medicines: whenever we wish a strong and permanent impression to be made on the alimentary canal, and through it on the neighbouring viscera or the system generally, Calomel by universal consent is adopted for such a purpose. (Form. 81, 88, 119, 161.) In larger doses it is one of the most efficient purgatives which we possess, especially when in combination with other cathartics: it appears to be particularly eligible in the diseases of children; and it is singular that infants can generally bear larger doses of it than adults. Dose, as an alterative, from gr. ss to j, night and morning; as a purgative, from gr. ij to gr. x, or in some cases even to gr. xv, or ℈j. Forms of Exhibition. That of pill; its insolubility and specific gravity render any other form ineligible. Officinal Preparations. Pil. Hydrargyri submuriat. comp: L. Impurities. Corrosive sublimate may be detected by precipitation being produced, by the carbonate of potass, in a solution made by boiling the suspected sample with a small portion of muriate of ammonia, in distilled water; calomel ought also, when rubbed with a fixed alkali, to become intensely black, and not to exhibit any trace of an orange hue.
Howard’s or Jewel’s Hydro-sublimate. Instead of subliming so as to obtain the calomel in a concrete state, as directed by the Pharmacopœia, the salt in the act of sublimation is exposed to aqueous vapour, and received in water. Being in a state of very minute division, it is lighter than common calomel in the proportion of three to five, and it cannot contain any corrosive sublimate. The French in their late codex have introduced a similar formula, under the title of “Murias Mercurii dulcis mediante aqua subtilissime divisus, juxta Methodum Josiæ Jewel.”
This Patent Calomel of Howard is undoubtedly to be preferred, and appears, in consequence probably of its minute division, to affect the system more readily than that made according to the Pharmacopœias.
Sub-murias Hydrargyri Præcipitatus. E.D. This is produced by precipitating a nitrate of mercury by muriate of soda; the preparation will generally contain a small portion of sub-nitrate, and it is on that account more liable to run off by the bowels in small doses: in other respects it is essentially the same as that procured by sublimation.
HYDRARGYRI SULPHURETUM RUBRUM. L.
Sulphuretum Hydrargyri rubrum. D. Olim, Hydrargyrus Sulphuretus ruber. P. L. 1817—Cinnabaris[[532]] factitia, 1745.