Upon the whole, then, from what has been said of this theory of the action of mercury in the cure of the _lues venerea_, it appears, that the cure can by no means be referred to the evacuation. The different arguments adduced in favour of that theory, we have endeavoured to shew, either proceed on wrong principles, or, although admitted in their greatest latitude, can afford no ground for any conclusion to support it. Evacuation, from its nature, whether supposed to operate by diminishing the quantity of circulating fluids, or by any change it can induce in their quality, can scarce be conceived to be a cause adequate to the cure of _lues venerea_. Evacuation does not produce a cure of the venereal disease, when it takes place in an equal, or even in a much greater degree, from the employment of other medicines, than when the disease is effectually removed from the use of mercury. And, _lastly_, the venereal disease is never more effectually cured by mercury, than when it is evident, from every mark by which the degree of evacuation can be determined, that the evacuation arising from it is least considerable. It may, therefore, with confidence be asserted, that mercury does not cure _lues venerea_ by evacuation. ------------------------------------------------------------------------ CHAP. III. _Concerning the Opinion, that Mercury cures Lues Venerea, by acting as an Antidote to the Venereal Matter._ 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.