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

by Andrew Duncan

The different modes in which mercury has been exhibited have very universally been reduced to two general heads, and referred either to its employment externally or internally. This division, however, is not without some degree of inaccuracy. Mercury, when taken internally, is very universally thrown into the system in general, without any particular attention to the affected part. When it is used externally, it is for the most part meant to act immediately on the diseased part. This, however, is not always the case; and sometimes the only thing intended by external application is its introduction into the system. But, when this is the case, its external employment is on precisely the same footing with its internal use. The proper distinction, then, depends not so much upon its being used either externally, or taken by the mouth, as upon the mode in which it is meant to act. Mercury, in every case, is intended either to act immediately upon the affected part, or to enter the circulating system.

If there be any truth in what has been said with regard to the action of mercury, the manner in which, in each of these ways, it comes to produce a cure, can readily be conceived, and is, at bottom, very similar. But, at the same time, these different modes of using the medicine are, in some measure, fitted for different purposes; and the influence which is exerted in the one way demands attention, which is not always requisite in the other. These methods of using mercury, then, may, with greater advantage, be considered separately than together. And what would claim consideration, in the first place, are those modes of application, in which the mercury is intended to act immediately upon the affected part.

From the opinion which was long entertained, that mercury, in every form, was a substance highly poisonous, it is not surprising, that, upon its first introduction into medicine, it should have been used externally only. In this way it seems also to have been first employed in the venereal disease. But, from the tendency which mercury has to enter the system, when used in any form, it is not surprising that its effects, as exciting salivation, should soon have appeared from its use externally. To a salivation thus excited, it was but natural to attribute the cure. Hence, from its external employment on its first introduction, there are few clear instances of its efficacy as acting immediately upon the venereal virus.

It is not, however, improbable, that, even in these early periods, some part of the influence which mercury had in the cure of lues venerea was to be ascribed to an immediate action on the venereal matter. In this way the good effects, in many cases, reaped from fomentations of cinnabar, one of the modes of applying mercury first put in practice, were certainly, in some measure, to be accounted for. It may, then, be affirmed, that the use of mercury, so as to act immediately upon the affected part, is a mode of applying it as early as its first introduction in the venereal disease. And, from examining the history of this distemper, as well as the various means which have, at different times, been employed in the cure, it will appear, that the immediate action of mercury on parts affected by lues venerea, particularly in places most easily reached, such, for example, as chancres, has always been a common intention in practice.

But enough has perhaps been said concerning the history of the immediate application of mercury. The present inquiry is with regard to the preparations now employed in this way, and the comparative advantage of each.

Among the first, and perhaps the most common forms in which mercury has been, and still is applied, with a view of acting immediately upon the affected part, are the mercurial ointments, cerates, and plasters. In this, as will appear from the table which has been given, the mercury is rendered active by division. Little difference can arise from the substance with which the mercury is combined during the triture. All these preparations, therefore, may, with propriety, be considered together. To this head may be referred, the blue ointments, mercurial cerate, and common plaster with mercury, of the London College; and the mercurial ointment, and plaster, of the Edinburgh.

These preparations seem to contain a very large proportion of mercury; and certainly, in their composition, a considerable quantity is blended. But it by no means follows, that the whole of that quantity is in an active state, or is in such a condition as to be capable of an union with the venereal virus. From late observations, it appears, that by much the greatest part of the mercury, although here rendered invisible, is still in its crude state. The effect, therefore, to be expected from them is by no means to be judged of from the quantity of mercury which has been employed in making them. And they are in reality much weaker preparations than might be imagined.

These are often employed as dressings to open sores. But the oily nature of the substances with which the mercury is here conjoined, prevents it from admitting of a ready union with the venereal virus. On this account, their power will be still farther diminished than from the cause formerly mentioned. Hence it may be concluded, that they are not the most proper mercurial applications for open ulcers. And indeed an examination of the state of the fact confirms this conjecture. For, upon inquiry, it will be found, that in such circumstances greater benefit may be reaped from other mercurial applications.

Mercury is often meant to act in the venereal disease, without any general affection of the system, or without entering the mass of circulating fluids, where it cannot come into immediate contact with the affected parts. These parts are often deep seated, and, at the same time, the integuments above them are unbroken. In such cases, mercury, applied in a form capable of penetrating, or of being absorbed, promises to be of service. That mercury, in the forms here mentioned, is in this situation, cannot be denied. And, in such cases, these forms have the peculiar advantage, which many others want, of admitting of an easy, gradual, and long continued application. Hence it is, that singular benefit is obtained from them in the resolution of nodes and buboes.

It may not be improper here to observe, that, for these intentions, particularly the last, which is an affection of the lymphatic glands, it is a very effectual mode of using the mercury, to apply it in the form of unction to those places from which the lymphatic vessels passing through the diseased gland take their rise. In this way, equal if not greater benefit will, in general, be reaped, than from immediately applying it to the tumor itself. By this means, the mercury will be carried with more certainty, and in greater quantity, to the affected gland, than it would be from pervading the substance of the integuments.