The efficacy of this preparation has not indeed, as far as I know, been confirmed by long or extensive practice. But, where it is proper to heal superficial ulcers, no application is of greater service than dressings of lint dipt in a solution of the corrosive sublimate in the proportion of half a grain to an ounce of water. The addition of a small quantity of compound spirit of lavender to this solution will give it a colour and smell different from those of common water, which, with some patients, are necessary conditions to an effectual application. In some circumstances already mentioned, the other modes of applying mercury to act immediately upon the diseased part may be preferable to this. But, where the only requisite to the healing of an ulcer is the destruction of that venereal virus at the part which supports a diseased state there, no application will answer the purpose with greater facility, safety, and expedition, than this solution. ------------------------------------------------------------------------ CHAP. VI. _Of the Mercurial Preparations intended to act in the cure of Lues Venerea by entering the System._ AN attempt has already been made to explain the operation of mercury, and the manner in which the venereal poison may be supposed to exist as a cause of disease. From these it might perhaps be concluded, that the introduction of mercury into the system was seldom requisite. And it might seem reasonable to infer, that all the advantage which could be obtained from mercury, might be had from its application in one or other of the ways already mentioned. So far, however, is this from being the case, that it is no uncommon thing with practitioners to inveigh, in the most express terms, against all external applications, those excepted which are of the mildest and most inactive nature. Mercurials have not been excluded, and the healing up of sores, by whatever external means it may be effected, has been considered as highly prejudicial. It can by no means be asserted, that these accusations against the external use of mercury are entirely without foundation. If properly understood, however, they may be true, without being any objection to the theory. It can never be imagined, that, from the destruction of the venereal virus at a particular part, by any application made there, it should be destroyed in the rest of the system. When, therefore, the venereal virus has already been absorbed, a radical cure cannot be expected from the healing of an ulcer. It may even sometimes happen, that, from a partial destruction of the virus in an ulcer, it may be healed externally, and, at the same time, absorption more considerably promoted than if it had remained open.