In all these cases, the mercury can only reach the mouth in the course of circulation. But, if it enter the mass of circulating fluids, it must, from the known and established laws of circulation, be equally carried to every different part of the body; and, among others, it cannot fail to be applied to those parts in which the venereal matter does exist. This first assertion, then, may be considered as sufficiently established; and, it remains only to show, that mercury, when it comes in contact with the venereal matter, has a power of destroying it. That mercury, when it is exhibited in such a manner as to be capable of conjunction with the venereal matter, has a power of rendering it inactive, is an assertion, which, it might be imagined, could be put to the test of experiment. But, experiments of this nature could not be performed without hazard; and, in the end, would perhaps be only undecisive. Although, however, no certain criterion has in this manner been obtained, there are not wanting arguments to render the opinion at least highly probable. In favour of the supposition, that mercury, in reality, possesses a power of rendering the venereal virus inactive, it may be observed, that an action in this manner is at least conceivable; and that it is analogous to what we have an opportunity of observing in other cases of nature. Many substances which possess the most active powers in nature, have these entirely destroyed, or totally altered, from combination with other substances. This holds remarkably of mercury itself, when united with sulphur. These, taken separately, are each of them substances of a most active nature; conjoined, the mixture becomes inert, or acts only as sulphur. From what has been said, then, it appears, that, in some cases, mercury by combination loses its active powers. But this fact will appear less singular, if such a destruction of powers holds not of mercury alone, but of other substances likewise. That it does, is exemplified in the mixture of sulphur with different metallics, as in the case of antimony. In the mixture of acids with alcalines, there is, if not a destruction of activity, at least a total change of properties. But to multiply instances of this kind, would be superfluous. Enough has been said to show, that there is at least nothing inconsistent with the common course of nature, in supposing, that such a mutual relation takes place betwixt mercury and the venereal virus. It may then be considered at least as a possible supposition, that, from the addition of the former, the latter is destroyed, or rendered inactive.