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.
CHAP. II.
Concerning the Opinion, that Mercury cures the Lues Venerea by the evacuation it produces.
There are few medicines with regard to the operation of which all practitioners are agreed. It is, however, by no means incumbent on him who means to establish the truth of any one opinion to overturn every hypothesis advanced on the same subject. But, as the arguments urged in favour of any hypothesis will have much less weight when another is previously believed to be true, and as the regulation of practice is, in every case, to a certain extent, founded upon theory, no inconsiderable advantage may be derived from overturning an ill-founded opinion, especially when it is generally received. The theory of the action of mercury, as well as of other substances, has afforded room for a diversity of opinions. For the reasons mentioned above, then, although it is by no means intended, that every opinion, with regard to the operation of that medicine, should here be considered; yet, as it is a very prevailing opinion, that the good effects obtained from mercury in the cure of lues venerea, depend upon its action as an evacuant; and, as a variety of seemingly strong arguments have been adduced in favour of that hypothesis, it will be necessary to examine how far they are sufficient to establish its truth.
In favour of the opinion, that mercury cures lues venerea by acting as an evacuant, the following arguments have been employed. It is alledged, that the good effects obtained from mercury in the cure of this disease, are in proportion to the evacuation which it produces; that the cure produced by mercury depends more upon the stimulant power of the preparation which is employed, than upon the quantity taken; and that the same good effects are obtained from other evacuants as from mercury; particularly, that the venereal disease is cured in a similar manner from the employment of guaiac. The arguments here enumerated, if not the only ones upon which this opinion is founded, are at least those which are principally employed. To examine, then, how far these are well founded, will be sufficient.
The first argument here adduced is, that the good effects of mercury are proportioned to the evacuation which it produces. This assertion, if allowed to be true, might, at first sight, appear to be a very strong argument in favour of the theory here adopted. But it is strong in appearance only; for, although it should be admitted, it in fact proves nothing.
But, even previous to this, it might be made a question, how far what is here assumed as a fact is well founded? And if it should appear, that mercury does not cure lues venerea in proportion to the evacuation which it produces, a strong argument might from thence be brought against this theory. But what may be said on this question will, with greater propriety, occur when the objections to the theory come to be adduced, than in attempting to refute and invalidate the arguments brought in its favour. At present, it will be sufficient to show, that, even allowing it to be true, it is no argument in favour of the supposition.
If it be true, that mercury cures lues venerea in proportion to the evacuation it produces, it may indeed, with some degree of probability, be concluded, that the evacuation and cure are not unconnected. And, if the evacuation is not the cause of the cure, it might at least from thence be inferred, that both of them depend upon the same cause; but it no more, unquestionably, follows from thence, that the evacuation is the cause of the cure, than that the cure produces the evacuation.