Many of those mercurials, which have not such an influence upon the stomach as to produce vomiting, upon entering the intestinal tube, act as purgatives. This effect of mercurials is, among other preparations, particularly remarkable on the use of the Coralline mercury, Prince’s powder, or calomel. Mercurials, which fail in producing either purgative or emetic effects, frequently act as diaphoretics. Diaphoresis, or even a profuse sweat, is often the consequence of many of the mercurials already mentioned. But when this effect is wanted, by means of mercurials, it is most commonly obtained by the use of a solution of corrosive sublimate. Mercury entering the circulating system exerts particular effects on different excretories; but in a more especial manner on those of the saliva. Salivation is an effect which may be obtained from the proper administration of almost every mercurial preparation; but for this purpose either the mercurial pills, or friction with mercurial ointment, are most frequently employed. Mercury may enter the system, exist in considerable quantity there, and be carried off by the different excretories, without producing any remarkable evacuation, or other apparent change, on the sound state of the body. That it is actually present in the system in such cases, is demonstrated by a general tendency to an increase in all the secretions. Mercury in this way, although it produces no visible effect on a healthy person, often procures the removal of a diseased state. Its action, therefore, in such circumstances, is termed _alterative_; an effect which may be obtained from most of the mild mercurials, especially when used in small doses. From these various modes of operating, it may readily be concluded, that mercury must be a powerful remedy in the cure of many diseases. The undoubted effects which it produces on the human system, when labouring under the venereal distemper, it would be both difficult and unnecessary fully to enumerate. It heals ulcers, removes swellings, alleviates pains, and cures eruptions. In short, the almost infinite variety of symptoms under which this disease makes its appearance may, by a proper application of mercury, be effectually eradicated from the constitution. From these effects, it is not surprising, that, in this distemper, mercury is the almost universal remedy. But, while it cannot be denied that peculiar advantages may be reaped from the employment of mercury in the venereal disease, it must at the same time be acknowledged, that, from the injudicious use of this medicine, very great evils have been produced. Whatever, therefore, relates to its proper administration, must be esteemed of importance. But to determine this, it is in the first place requisite to ascertain the principles upon which it operates. In treating of the present subject, then, an examination of the most probable opinions, with regard to the mode of its operation in the venereal disease, first claim our attention.