As far as we have considered the effects of mercury, its debilitating tendency seems to arise from the evacuation it occasions. But it debilitates in another way, which has not been sufficiently attended to. Whatever weakens the stomach and bowels is soon felt in every part of the system, and even medical men, as far as I can judge, are not in general sufficiently aware of the bad effects which often arise from the internal use of mercury. To prescribe calomel, one of the most active preparations of this medicine, with the same freedom, and for the same purposes, as rhubarb or senna, is in my opinion altogether a misapplication of it. Few things apply to the stomach and intestines a more hurtful irritation. I have often seen temporary dysentery induced by a few doses of calomel, and I am convinced from many cases that its habitual or even occasional use as an aperient, however innocent it may seem at the time, seldom fails at length to debilitate the powers of digestion, and is often productive of still worse consequences. Calomel is frequently given to children because it has little taste, and may be given in small compass. But it is better to give a milder medicine, tho’ a larger quantity may be required. Perhaps the smallness of the quantity in which it operates is of itself a sufficient objection, for there is no aperient which operates in very small quantity that operates mildly, as we might have foreseen, although the trial had not been made. For my own part, I know of few instances in which the internal use of mercury seems proper. There are some cases where powerful means are required to rouse the bowels to action, or a strong stimulus applied to their exhaling vessels is beneficial; and mercury is sometimes successfully employed internally for the removal of worms, but in ordinary cases we can surely with equal advantage use a less irritating medicine. When mercury is not employed as an aperient, but for the purpose of impregnating the system, what advantage is there in giving it by the mouth. It seldom happens that we cannot give as much as we wish by the skin. I have known many who were less debilitated by an ounce of mercury taken by the skin, than by half a dram received even in the smallest doses into the stomach.