fæces seem to be equally suited to the several bowels along which they descend, though they grow perpetually more putrid and acrimonious in their descent; i.e. there is an abatement of sensibility in the bowels, which corresponds to the increase of acrimony in the fæces.
If it be objected here, that honey, mercurius dulcis, &c. offend the stomach and bowels often, though pleasant or insipid in the mouth, I answer, that such bodies require time, heat, solution, &c. before the whole of their qualities can be exerted.
Secondly, The particular manner in which opiates, fermented liquors, grateful aliments, and narcotics, may act first upon the stomach and bowels, and afterwards upon the whole body, agreeably to the doctrine of vibrations, has been given above in treating of sleep.
Thirdly, The action of vomits, purges, and acrid poisons, such as corrosive sublimate, is very reconcileable to this doctrine, by only supposing, that they excite very vigorous vibrations, and that these are communicated to the muscular coats of the stomach and bowels, to the muscles of the abdomen, and, in violent cases, to the whole muscular and nervous system. I shall consider the automatic motions, which arise from these causes, below, under a particular proposition. It may serve to shew the analogy of the sensations, and the general nature of active medicines, to observe, that these will often operate in several ways, viz. as vomits, purges, diuretics, diaphoretics, sternutatories, vesicatories, and corrosives, by a change of application and circumstances.
Fourthly, Since the meats, to which particular persons have an antipathy, and from which they receive violent ill effects, are, in general, highly grateful to others, one may perhaps conjecture, that the vibrations excited by these meats in the stomachs of those who have an antipathy to them, do but just pass the limits of pleasure; so as to diffuse themselves much farther, and more powerfully, than if the first impression was very painful.
Lastly, The connexion between the sensations of the tongue and stomach, and consequently between the manners of explaining them, may be inferred from the office of the taste, as a guide and guard to the organs of digestion; which is very evident, in general, in all animals, notwithstanding a few exceptions, more especially in men.
Natural hunger may be reckoned a pleasure in its first rise, and to pass into a pain only by increase and continuance. We may suppose therefore, that during hunger the nerves of the stomach are so irritable, as that the common motions of the muscular coat, and the impressions made by its contents in consequence of these motions, excite such vigorous vibrations, as
