Page:Essays on the active powers of the human mind; An inquiry into the human mind on the principles of common sense; and An essay on quantity.djvu/450

430 sensations of taste, hearing, colour, heat, and cold: so that what hath been said of this sense, may easily be applied to several of our senses, and to other operations of the mind; and this, I hope, will apologize for our insisting so long upon it.

I. part of what hath been said of the sense of smelling is so easily applied to those of tasting and hearing, that we shall leave the application entirely to the reader's judgment, and save ourselves the trouble of a tedious repetition.

It is probable that every thing that affects the taste, is in some degree soluble in the saliva. It is not conceivable how any thing should enter readily and of its own accord, as it were, into the pores of the tongue, palate, and fauces, unless it had some chemical affinity to that liquor with which these pores are always replete. It is therefore an admirable contrivance of nature, that the organs of taste should always be moist with a liquor which is so universal a menstruum, and which deserves to be examined more than it hath been hitherto, both in that capacity, and as a medical unguent. Nature teaches dogs and other animals to use it in this last way; and its subserviency both to taste and digestion shows its efficacy in the former.

It is with manifest design and propriety, that the organ of this sense guards the entrance of the alimentary canal, as that of smell, the entrance of the canal for respiration. And from these organs being placed in such manner, that every thing that enters into the stomach must undergo the scrutiny of both senses, it is plain that they were intended by nature to distinguish wholesome food from that which is noxious. The brutes have no other means of choosing their food; nor would mankind in the savage state. And it is very probable that the smell and taste, nowise vitiated by luxury or bad habits, would rarely, if ever, lead us to a wrong choice of food among the productions of nature; although the artificial compositions of a refined and luxurious cookery, or of chemistry and pharmacy, may often impose upon both, and produce things agreeable to the taste and smell, which are noxious to health. And it is probable, that both smell and taste are vitiated, and rendered less fit to perform their natural offices, by the unnatural kind of life men commonly lead in society.

These senses are likewise of great use to distinguish bodies that cannot be distinguished by our other senses, and to discern the changes which the same body undergoes, which in many