In short, the objections to the use of mercury by the skin, seem all to resolve themselves into the two above treated of, the debility occasioned by an increase of some of the excretions, and a greater susceptibility to the effects of cold.[B] While there are the same objections to the internal use of mercury, there are far more weighty ones, which are not the less so, because we cannot with the same precision define them. All that we know of them is, that they chiefly consist in a debility of the stomach and intestines, which gives rise to the various dyspeptic complaints, flatulence, acidity, diarrhœa, and dysentery, effects which I have so often witnessed from the internal use of mercury, that I have for some years almost wholly abandoned it, except in the cases above alluded to. [B] It is unnecessary to notice a variety of groundless opinions, respecting the effects of mercury, which prevail among the vulgar, that it remains for ever in the system, causes a rottenness of the bones, &c. These are similar to the prejudices which prevailed respecting the bark for a long time after its introduction into practice, that it was formed into masses in the stomach and bowels, from which it could never be expelled; that nobody survived the use of it more than seven years, &c. The precautions suggested by what has been said will, I believe, in every instance, prevent the bad effects of mercury, with the exception of the symptoms of salivation, which it is now and then necessary to induce. It will be proper to take a cursory view of these precautions. * * * * * As by promoting the excretions, mercury tends to debilitate, it must be used with caution in weak habits, and its debilitating effects should be counteracted by the use of such strengthening medicines as are adapted to the case in which we employ it. The debilitating effects of mercury, however, are not such as many suppose. In a habit of ordinary strength, a moderate course of mercury, properly conducted, produces little debility, and I have seen many under such a course recover both their strength and flesh. The mercury gives vigour, by removing the cause which impairs it. With caution there is no danger in making a trial of mercury in the most debilitated habit. In such the quantity first employed should be too small to produce any effect whatever. Let it be gradually increased; if, as often happens, the strength improves, let it be continued; if the strength be much impaired by it, it should be laid aside.