On this case it is of importance still to remark, that it affords, in the strongest manner, an argument against what our authors say, p. 86, that “mercury acts by supporting the excitement of the whole body, it invigorates each particular part; and thus occasions, to a certain extent, the regeneration of those organs which may have been injured by disease.” In the instance adduced, there is no evidence of a stimulus upon any other part of the system than the bowels, which were already debilitated or diseased in such a manner that they could not bear it. The system in general, instead of being excited, was sunk and debilitated from the very first moment, until at last the excitement terminated entirely by the patient’s death. But further: There is very little probability that mercury or any other medicine whatever can prove a general stimulus, and that for the following reasons. 1. No medicine can assimilate with the substance of the body. Medicines properly so called are here alluded to. Food or drink of any kind taken for the support of the body while in health, however they may act medicinally upon occasions, are excepted. 2. The body is composed of many various substances, each differing in its nature from the other. The nature of the medicine, whatever it may be, is uniform, and cannot act upon substances of different kinds in an uniform manner; and without this there can neither be an universal stimulant, nor an universal debilitant. 3. All medicines, being incapable of assimilation with the body, must be considered, when taken into it, as foreign matter; and the introduction of them at any rate is in fact the creating of a disease. This is evident from multitudes of instances where people by quacking with themselves, and taking medicines unnecessarily, have destroyed their health. 4. As every medicine has one peculiar nature, and one mode of action in consequence of that nature, it must, when introduced into the body, where there are fluids of various natures, act upon one of them more than the rest; and this may be called the _chemical_ action of that medicine upon the body.