On the Vital Principle/Book 2/Prelude to Chapter 9
Modern science confirms Aristotle's judgment concerning the nature of odour, for it is said "to be a curious and interesting problem, requiring much more investigation than it has hitherto received;" and, according to Cuvier[1], "of all the substances which act upon our senses, those which produce the sensation of smell are the least known, although their impression has the liveliest and deepest influence upon our economy." But the reason assigned in the text for this relative imperfection of our smell is indefinite and questionable; for "although man's nostrils are less complicated than those of any animals save the quadrumana, he is the only creature whose smell is fine enough to be affected by unpleasant odours" It may be doubted, besides, whether any sensation can be, as is implied in the text, so pure as to be freed from all mental or corporeal association; but when man's smell is compared with that of birds and beasts of prey, it may be granted that, within a certain range of impressions, it is relatively duller and coarser than with them. It is, however, assumed, that sight and smell, when perfect, have the faculty of perceiving colours, and odours purely, unassociated, that is, with any impression grateful or otherwise; and thus, as man's smell was held to be imperfect, he was supposed to be sensible of odours as creatures with hard, that is, compound eyes are of colours. For such creatures[2] (crustacea, insects and others), having their eyes uncovered, being without lids that is, see objects which are at a distance "indistinctly, and as if they were looking through congenitally attached eye-lids."