The three preparations of mercury which have already been treated of, when compared with many others, may be esteemed mild. There are a different set, which, in opposition to these, may be termed _acrid_. Of the acrid preparations, not a few have likewise been used in the cure of _lues venerea_, and for this purpose introduced into the system in different forms. To treat of all of these would not only be deviating from our first intended plan, but would lead to many unnecessary repetitions, and needless inquiries, with regard to medicines which are now by no means in common use. Calomel and corrosive sublimate may be esteemed the two extremes of the acrid preparations; the first being the mildest, the last the most stimulant, which is, in the present practice, ever used internally. These two are, at the same time, the acrid preparations which are perhaps most frequently employed in the cure of _lues venerea_. To treat of these therefore will be sufficient. Calomel, it has been observed, may be considered as the mildest of the saline preparations of mercury. In this preparation, the basis of which is the corrosive sublimate, the mercury is reduced to the form of a saline compound, by means of the muriatic acid. But it is afterwards rendered less acrid, from the addition of fresh mercury in repeated sublimations. It has by many been esteemed the most useful of the mercurial preparations, not less for other purposes for which mercury may be employed than for the cure of the venereal disease. The good effects which may be obtained from its use in this complaint are confirmed by undoubted experience. And, when it is introduced into the system, there can be no question with regard to its efficacy in destroying the venereal virus. Calomel acts as a more general stimulant in the system than the milder preparations of mercury. And it discharges itself by the different excretories, when present in the mass of circulating fluids, in no very considerable quantity. Hence, it can be less accumulated in the system than the other preparations formerly mentioned. To this circumstance it is probably owing, that it less frequently excites salivation than these do. If, indeed, it be given in large doses frequently repeated, and does not at the same time affect the intestinal canal, it will excite salivation. From this, it may be concluded, that then the active mercury is present in the system in a very considerable quantity. But, when in this way, even such an accumulation can be obtained, it is to be considered only as on the same footing with the milder mercurial preparations, in those constitutions which are readily salivated. Here, therefore, as in habits naturally disposed to salivation, the presence of any quantity of mercury in the system will be very transient, and a salivation occurring will often frustrate the cure to be expected from it.