- Hydrargyrum Corrosivum Sublimatum. Br. - Hydrar-Gyri Bichloridum. Lond. - Deutochloride of Mercury. - Bichloride of Mercury. - Perchloride of Mercury. - Chloride of Mercury.

Corrosive sublimate is prepared by first forming, as in the process for calomel, the sulphate of the deutoxide of mercury, and afterwards submitting this to sublimation in connection with chloride of sodium. An interchange of principles takes place, by which sulphate of soda and the deutochloride of mercury are formed, of which the former remains behind, and the latter passes over in vapour, and is condensed in a proper recipient.

Properties

As kept in the shops, corrosive sublimate is usually in heavy, white, translucent, crystalline lumps, unchangeable in the air, inodorous, of an exceedingly acrid, styptic, metallic, and persistent taste, soluble in eighteen or twenty parts of cold, and three of boiling water, and very soluble in alcohol and ether, the latter of which will partially abstract it from its watery solution. it is soluble, also, without change, in sulphuric, nitric, and muriatic acids. The alkaline chlorides unite with it, forming double chlorides, and thus rendering it more soluble in water. it melts when heated, and, at a higher temperature, is volatilized without change.

Incompatibles. The alkalies and alkaline earths decompose it, causing a red, orange, or yellow precipitate of the deutoxide of mercury, with the exception of ammonia, which produces a white precipitate. The alkaline protocarbonates also throw down the red oxide. it is decomposed by the soluble salts of lead and silver, by tartar emetic, iodide of potassium, and the soluble sulphurets. With albumen and fibrin it forms insoluble, or but very slightly soluble compounds, which, however, if recent, are dissolved by acid and alkaline liquids, and by solutions of the chlorides of potassium, sodium, and calcium. in consequence of the combination which it forms with albumen and fibrin, it protects animal substances against putrefaction. The solution, when exposed to light, is gradually decomposed; but the change is prevented by the presence of the alkaline chlorides.

Effects on the System

Corrosive sublimate is a powerful local irritant, producing, when applied to any surface, whether internal or external, either irritation, inflammation, or corrosion, according to the quantity applied, and the degree of concentration. its corrosive property is ascribable to its affinity for the albuminoid constituents of the tissues, with which it unites chemically, with the effect of producing disorganization. its external effects, however, will be considered more fully under the escharotics.

Taken internally, in very small doses, it is capable of operating on the system, without disagreeably affecting the stomach and bowels. The opinion has been very generally entertained, that it has less tendency than most other mercurials to produce sore-mouth, even while bringing the system at large under its influence, as evinced by a somewhat increased action of the heart, an augmented flow of perspiration or of urine, and the curative effects which often result. There is probably some truth in this opinion, though the fact, admitting it to be such, is not very satisfactorily explicable, in accordance with the most probable views of the action of mercurials. Perhaps, however, the difference between it and the other preparations, in this respect, may be rather apparent than real. We give the milder preparations more freely, it may be, than is necessary for their curative effect, because we have no apprehension of local injury from an over-dose. Perhaps, were we to prescribe them less freely, we might witness all the effects which we obtain from corrosive sublimate, with an equal exemption from ptyalism. But, in relation to this mercurial, we are compelled to give it in very small doses, to avoid injury to the stomach and bowels. On account of this apparent peculiarity of curing syphilitic diseases without salivating, corrosive sublimate has long been a favourite medicine with empirics, who profess to cure syphilis without mercury.

Even in ordinary medicinal doses, the medicine sometimes acts as an irritant, producing nausea, griping pains, and sometimes vomiting or purging, though the former effect is rare. This result may generally be obviated by combining it with a little opium. if, however, it be persevered with, under such circumstances, especially in somewhat large doses, there is danger of producing a chronic inflammation of the alimentary mucous membrane, which may have serious consequences.

Though less liable to salivate, in ordinary doses, than other mercurials, it will generally, if persisted in, sooner or later affect the mouth, and sometimes violently so. I have before referred to a case, which fell under my own observation, in which salivation was apparently induced by two doses of one-sixth of a grain each.

Poisonous Effects

When taken largely, corrosive sublimate acts as a powerful corrosive poison. if given in successive doses, so as to bring about the poisonous results gradually, severe ptyalism is often induced, with all its most unpleasant accompaniments. in such cases, there is usually, after each dose, more or less colicky pain, with nausea and vomiting; and the patient dies at length of the combined effects on the stomach and bowels, and upon the mouth and fauces, in which the lungs not unfrequently participate, as indicated by dyspnoea, cough, and Woody expectoration. Tremors and paralysis sometimes precede death.

When a single poisonous dose has been taken, large enough to destroy life, the symptoms are a strong acrid metallic taste; a sense of constriction and burning in the oesophagus; excruciating pain in the stomach, which, however, is sometimes wanting; nausea, and frequent vomiting of mucus, often mixed with blood; and generally violent purging, with or without blood in the stools. The system is usually greatly prostrated; and cramps in the extremities, and sometimes convulsions precede death. Not unfrequently the patient lives several days, in which case the true mercurial ptyalism is apt to occur. Profuse discharge of saliva sometimes takes place much earlier; but this is owing to the direct irritant action of the poison on the mouth, or a sympathetic result of the gastric disturbance. if the patient survive the gastro-enteritis, he sometimes lingers long under the disease of the mouth and fauces, which, by the occurrence of sloughing and extensive ulceration, may prove fatal.