It is found by chymists generally to contain mercury, arsenic, lead, sulphur, and sometimes copper, silver, and other metals[48]. When it is melted by fire, or deflagrated with half its weight of nitre, it becomes a poison. But if antimony, or its regulus, is mixed with an equal portion of common salt, and calcined with a gentle heat, stirring it constantly, and afterwards washing it with pure water, it becomes a gentle diaphoretic. The mildest preparation of antimony; its white calx, which may be safely taken to the quantity of some drachms, if melted with an equal portion of nitre, a little powder of charcoal, and a small quantity of animal fat, is immediately rendered poisonous. If antimony is melted with a fourth part of salt of tartar, a salutary medicine is obtained; but if the same process is performed with two or three times that quantity of the salt, so nice is the management of this wonderful mineral, in place of a medicine it becomes a poison[49] When antimony is combined with other medicines, as it frequently is by practical physicians, unless the composition is directed with chymical skill, it may be so changed, or, in the language of the chymists, decomposed, as totally to alter its usual qualities. By marine acids the activity of antimonials is increased, and they are rendered corrosive, or virulently emetic and purgative; but by the addition of the nitrous acid this virulence is diminished or destroyed, and they become mild diaphoretics[50]. Such being the uncertainty and variety in the operation of antimonial preparations, it cannot be improper, since they are now in common family use, to lay before the public the objections against the general application of them, which arise from the accurate observations of the best chymists, and most experienced physicians; since it is not improbable, that many who deal them out with a liberal hand, and with the most charitable and benevolent intentions, would dread the danger of a drug, which though published as an infallible remedy, may, without great skill and precision in the direction of it, in place of a remedy become a poison. But the ultimate decision of this point must depend on the real effects of antimonial medicines on the human body, which are therefore now to be considered. SECTION IV. _Of the preparations of antimony, and their medical effects._ The limits to which dissertations of this kind ought to be confined will not permit us to enter into a minute detail of the various antimonial preparations which may be found in every dispensatory. Those in most frequent use are calx of antimony, crocus of antimony, antimonial wine, tartar emetic, and kermes mineral.