else the taste would be much more variable than it is, and continue to change more after adult age, than it is found to do in fact. It may perhaps change faster in the use of a high diet than of a low one; which would be an evidence of the reality of the cause here assigned.
Thirdly, The pleasant and painful impressions which particular foods and medicines make upon the stomach, always either accompany the taste, or follow it in a short time; and by this means an association is formed, whereby the direct pleasantness or nauseousness of the taste is enhanced, if the impressions upon the tongue and stomach be of the same kind; or diminished, and perhaps overpowered, and even converted into its opposite, if they be of different kinds. For if the two impressions A and B, made upon the tongue and stomach respectively, be repeated together for a sufficient number of times, b will always attend A upon the first moment of its being made. If therefore B be of such a magnitude as to leave a trace b sufficiently great, the addition of this trace b to A, the impression made upon the tongue, may produce all the changes in it above-mentioned, according to their several natures and proportions. This follows from the doctrine of association, as it takes place in general; but here the free propagation of vibrations from the stomach to the mouth, along the surface of the membranes, adds a particular force. In like manner a disagreeable taste, by being often mixed with a pleasant one, may at last become pleasant alone, and vice versâ: hunger and satiety may also, by being joined with particular tastes, contribute greatly to augment or abate their relish. And I believe it is by the methods of this third kind, that the chief and most usual changes in the taste are made.
Fourthly, The changes which are made by associations with mental pleasures and pains, or bodily ones not belonging to this organ, as with fine colours, music, &c. receive a like explication as the last-mentioned instances of associations. Here the pleasure excited in the eye or ear overrules the taste at first: afterwards we may suppose the organ to be so altered by degrees, in respect of the disagreeable taste, from its frequent impression, or other cause, as to have the solution of continuity no longer occasioned by its action. It is probable also, that the evanescent pleasures of sight and hearing, at least pleasant vibrations in the parts of the brain corresponding to these two organs, accompany these tastes ever afterwards.
It may be observed here, that the desire of particular foods and liquors is much more influenced by the associated circumstances, than their tastes, it being very common for these circumstances, particularly the sight or smell of the food or liquor, to prevail against men’s better judgment, directing them to forbear, and warning them of the mischiefs likely to arise from self-indulgence.
