One very important advantage, more directly obvious than this, and of a kind which every one may be disposed more readily to admit, is afforded by our senses of smell and taste, in guiding our _selection_ of the substances which we take as alimentary. To the other animals, whose senses of this order are so much quicker, and whose instincts, in accommodation to their want of general language, and consequent difficulty of acquiring knowledge by mutual communication, are providentially allotted to them, in a degree, and of a kind, far surpassing the instincts of the slow but noble reflector _man_, these senses seem to furnish _immediate_ instruction as, to the substances proper for nourishment, to the exclusion of those which would be noxious. To _man_, however, who is under the guardianship of affections more beneficial to him than any instinct of his own could be, there is no reason to believe, that they do this _primarily_, and of themselves, though, in the state in which he is brought up, instructed with respect to every thing noxious or salutary, by those who watch constantly over him in the early period of his life, and having, therefore, no necessity to appeal to the mere discrimination of his own independent organs, and, still more, as in the artificial state of things, in which he lives, his senses are at once perplexed and palled, by the variety and confusion of luxurious preparation, it is not easy to say, how far his primary instincts,--if it had not been the high and inevitable dignity of his nature to rise above these,--might, of themselves, have operated as directors. But, whatever their _primary_ influence may be, the _secondary_ influence of his organs of taste and smell is not the less important. When we have once completely learned what substances are noxious, and what are salutary, we then, however similar they may be in their other sensible qualities, discriminate these as often as they are again presented to us, by that _taste_ or _smell_, which they affect with different sensations; and our acquired knowledge has thus ultimately, in guiding our choice, the force and the vivacity of an original instinct. HEARING.