Employment as a Supposed Sedative. in epidemic cholera, dysentery, yellow fever, etc., it has been recommended in large doses as a sedative agent. it is asserted that, when given very largely in these cases, so far from causing local or general excitement, it produces, on the contrary, a remarkable sedative effect, allaying the local irritation, checking vomiting and purging, lowering the frequency and force of the pulse and the heat of skin, and greatly contributing to the cure. As to the quantity administered, there have scarcely been any fixed limits; and experiment has run wild, in the latitude of choice, which, according to this theory, is permitted to the adventurous practitioner. The old doses have been quite disregarded. Twenty grains every half hour, hour, or two hours have been quite within bounds, in cases of epidemic cholera. Two drachms at the beginning, and a drachm every hour or two afterwards, have been given; and an instance is recorded, in which thirty drachms were administered in 48 hours, with moderate ptyalism and recovery; and fifty-three drachms in 42 hours, in a fatal case, without observable effect. (Pereira, Mat. Med., 3d ed., p. 854.) in this country, the remedy has been used in teaspoonful doses; and I have before mentioned an instance, in which a pound is said to have been given in the course of the disease. I have never used calomel in this method, and can say nothing in regard to it of my own knowledge. Why it is generally safe, the reader can understand. Perhaps only from ten to twenty grains act dynamically; all the rest is inert. But it does not follow that this inert portion may not be operating advantageously by its physical properties. it is not impossible that, diffusing itself over the mucous surface, adhering everywhere to the villi, and filling up the follicles, it may form a protective coating for the tender surface, which may guard it against the irritating contents of the bowels, as a piece of caoutchouc, or gutta percha plaster, will protect an external inflamed surface, and thus favour the subsidence of the inflammation. its presence and weight may also interfere with and depress the function of the irritated part, and thus check the excessive secretion. Upon similar principles, it is thought that subnitrate of bismuth restrains diarrhoea, and indeed cures the complaint. All this may be true; but I doubt whether the advantage gained is equal to the hazard. Some may be benefited; many may be unaffected, neither receiving good nor harm; but there may be some, as before suggested, to whom, under certain circumstances, the measure may do irreparable injury; and, unless we had more satisfactory evidence of a good effected which could be attained in no other way, it would be the part of prudence not to imitate the practice.

Administration

The dose of calomel for an adult is from five to twenty grains; for a child two or three years old, about four grains. One or two grains may be given to infants under a year. it may be administered in powder, mixed with syrup or molasses, or in the form of pill, which should be freshly made, so as to be readily broken up in the liquids of the stomach. Should it not operate in six or eight hours at furthest, it should be followed by another cathartic, as castor oil, one of the saline purgatives, or senna, to hasten its action. To ensure its operation, and increase the purgative effect, it is not unfrequently given in combination with other cathartics, as rhubarb, aloes, jalap, scammony, compound extract of colocynth, etc. it is one of the ingredients of the compound cathartic pill (U. S.), which may often be advantageously employed in the diseases above mentioned, when calomel is indicated. But in all cases in which the stomach is irritable, the calomel should be given alone.