Observations on the Operation and Use of Mercury in the Venereal Disease

by Andrew Duncan

It is an undoubted fact, that mercury, by proper management, cures lues venerea. From the arguments already adduced, it has been concluded, that the cure, thus obtained, is not the consequence of evacuation. Having rejected this prevalent opinion, then, it next remains to say, in what manner a cure is produced.

It has long been an opinion, very generally received, that mercury is a substance capable of destroying the venereal virus; or that, from being united with this virus, possesses a power of rendering it inactive. Many arguments tend to prove, that this is in reality the case; and that in this manner it cures lues venerea. But, at the same time, this theory is not to be considered as without difficulties. The first that occurs, is, with regard to the mode in which an opportunity is afforded for a mixture of the mercury with the virus.

It is, in general, imagined, that mercury may destroy the venereal virus in the mass of circulating fluids. The venereal virus is unquestionably taken into the human system by the absorbent vessels to which it is applied; and, before it can reach various parts of the body, in which it evidently manifests itself, it must enter the general mass of fluids. We cannot, then, consider it as a supposition totally absurd, that mercury, if it be capable of destroying the activity of the venereal matter, may produce that effect while the virus is present in the general mass of fluids. Many objections, however, may be urged against this supposition; and, if it be adopted, it must be allowed to be with difficulties.

If mercury destroy the venereal virus, while it exists in the mass of circulating fluids, it must produce this effect, either by an alteration of the general mass; or by acting more particularly on the venereal matter itself. The whole mass of circulating fluids, taken collectively, is a very considerable quantity of matter. The action, therefore, of a small proportion of mercury, as producing any change upon it, cannot be very great. It is not easy to conceive, then, how a destruction of the venereal virus should arise from any alteration which the mercury is capable of producing on the general mass.

The difficulty occurring to the first supposition here made, would naturally lead us to consider the second. But that the action of mercury, while it exists in the mass of circulating fluids, should be exerted on the venereal virus alone, is a supposition equally unsatisfactory as the former. Before this can be imagined to be the case, it is necessary to suppose, that there exists, between mercury and the venereal virus, some particular attraction. Such an attraction, however, is a thing as yet by no ways proved to exist; nor indeed does there seem to be any shadow of reason to suppose that it does exist.

Although, then, it cannot be denied, that mercury and the venereal virus may exist in the mass of circulating fluids at the same time; yet, from what has been said, the supposition, that the activity of the virus is then destroyed, will appear to be attended with many difficulties. It cannot, it is true, be alledged, that, from any thing which has been urged, this supposition is refuted. That it may perhaps, in some degree, act in this way, is by no means impossible. But it is to be remembered that this is a hypothesis supported by no proof; and the more imaginary any opinion is, the less easily can it be overturned. The present opinion, then, may be set aside, for reasons, which, in other respects, would be insufficient for its being rejected; and this the more readily, if another and more probable hypothesis can be advanced which is not liable to the same objections.

To determine the manner in which mercury acts on the venereal virus, it might seem requisite that the nature of this poison should first be ascertained. In what the activity of the venereal virus consists, it is difficult, perhaps impossible, to say. Various conjectures have indeed been offered with regard to it. But what has hitherto been advanced upon that subject is so hypothetical as scarce to deserve a serious refutation. What could, therefore, be derived from an inquiry of this nature, without a more perfect knowledge of the subject than has hitherto been attained, would be but of little utility.

But, although the peculiar nature of the venereal virus, and those principles in consequence of which it becomes active, are unknown, yet its general effects, as acting on different parts of the human body, are sufficiently obvious. The parts morbidly affected by the venereal virus, at different times, put on different appearances. This, however, is in common to all of them, that, when reduced to the state of an open ulcer, they discharge an infectious matter capable of propagating the disease. It cannot therefore be doubted, that the venereal matter occasions the morbid affections there observed from its actual existence at these places.

As the places evidently affected by the venereal poison are frequently very distant from those to which the poison has been first applied, and do not lie in the course of the absorbents, it can only be carried to them in the course of circulation. But, even while the poison is present in the circulating system, no change can be detected on the general mass of fluids; nor in by much the greater part of the solids in the body. Many changes may take place in the fluids of the human body which cannot be said to constitute a diseased state. That such changes may be esteemed morbid, it is necessary that they should manifest themselves over the system in general. If, then, we are to judge by these principles, it follows, that the venereal poison does not produce a morbid state in the general mass of fluids. It evidently acts as a cause of disease in particular parts, whether it first comes to be applied to these by immediate contact with external objects, or arrives at them in the course of circulation. Probably it acts as a morbid cause in these places, from being, by some accident, detained there, in consequence of which the quantity of the poison is increased by assimilation. This opinion, with regard to the influence of the venereal virus in producing the disease, will lead to a different conjecture concerning the operation of mercury, as tending to destroy it.

If this opinion be true, the venereal poison may be supposed to be productive of disease, only when collected at particular parts. This would lead us to conclude, that, if mercury possess a power of destroying the venereal virus when it comes in contact with it, it can only produce a cure of lues venerea from being topically applied to the poison collected at particular parts of the body. Mercury, however, unquestionably does produce a cure of the venereal disease. If, then, it can be shewn, that mercury in reality is an antidote to the venereal virus; and that, previous to its producing a cure, it is topically applied to those parts in which the venereal virus is lodged, we may reasonably conclude, that the cure obtained from its use is to be referred to its action as an antidote from topical application. To establish this supposition, then, it is first necessary to show, that the mercury is in reality topically applied to the venereal matter.