Thus, we all know that certain odorous substances particularly predispose us to nausea ; that certain ap petising substances, and the odour of preparations made with vinegar, gum-dragon, etc., act upon the salivary secretion, and, as we say, make our mouths water ; that perfumes and certain specific odours have an aphrodisiac action ; that with certain impressionable pemns the presence of certain odours produces profound disturb ances, sometimes even syncope ; that finally, in certain persons subject to headaches, it is no longer the sensorium as a centre of reception for the moral sensibility that is affected by them, but the sensitive sensoriunz, the brain itself, that is impressed in a painful manner, in certain of its histological elements. Many persons are aware that the odour of certain flowers that make an agreeable impression on their sensoriunz produces a painful after effect, as though they had to do with a physical ache.
Olfactory excitations are, like their fellows, capable of being stored up in the seissorium in the form of per sistent reminiscences, and of being associated either with visual impressions or with those sensitive impres sions which have been simultaneously imprinted upon us. They are similarly linked with our ideas, and the sentiments that have accompanied their genesis, so that the chance arrival of a perfume in the nostrils, is suffi cient to awake a whole series of contemporary memories, and of emotions which arise in consequence, and recall to us the moment and the place in which the perfume was first inhaled.
Olfactory impressions, again, furnish the intellect with precise and specific data, which, when preserved in the form of reminiscences and compared together, become materials by means of which we fortify certain judg ments.
Thus when associated with their fellows, gustatory excitations, which they perfect and complete in the act of deglutition, they furnish us with precise notions respecting the flavour and sapid qualities of the sub stances we are eating.
They also warn us, by an act of memory and experience, of the presence of foetid emanations float ing in the air or in the liquids we absorb. They are thus like advanced guards that watch incessantly over the security of the operations of the vegetative life of the hufnan being.
Evolution of Gustatory on the surface of the buccal and lingual mucous membranes, in the terminal expansions of the glosso-pharyngeal and lingual nerves, gustatory impressions are thence pro bably distributed within a definite region of the optic thalamus; but up to the present time, we are not in a position to demonstrate the precise place of their con densation. From this point they are, like all other im
pressions, distributed in the cerebral cortex, their area of distribution here also not being yet determined.
r. Intimately connected with their companion olfac tory impressions, in their method of impressing the sen sorium, and being constantly associated with them, they owe to this union a notable portion of their energy, and the various forms in which they reveal themselves in us. Thus it is that the capacity we have for tasting the flav our of certain sapid substances, such as the bouquet of some wines, is only the combined effect of olfactory and gustative impressions, these latter being quite incapable of producing such a result, as we may assure ourselves by stopping our nostrils and allowing our gustatory im pressions to act alone. We then perceive how restrained is their field of activity.
They give us the unanalysable and specific notion of sweet, saccharine, salt, acid, acrid, and bitter savours. The diapason of tones that they set vibrating in the seizsorium is, as we can see, by no means rich in varied shades.
2. Genesis of the Notion of Goca' and Evil.—On the other hand, they present this very characteristic quality, that the mode in which their extreme notes affect the scnsoriunz is so significant and so typical that they con stitute for it two quite peculiar and original conditions, which assist us in judging and comparing certain pheno mena of the moral order.
Thus, when the natural sensibility of our gustatory nerves has been gratified, when a sapid substance has brought them into a pleasant condition, this peculiar state of satisfaction is transmitted to the sensorium, is there propagated, and produces an analogous condition ; and this analogous condition, initiated by the peripheral nerves, becomes a subjective notion, the notion of good ness—equivalent to the notion of beauty excited in the sensorium by the optic nerves when agreeably impressed. We say then that a thing is good when it has fully satisfied our gustatory nerves ; so that this peculiar word, primarily applied to the agreeable perception of a sapid substance, is generalized in the sensorium, and becomes a moral appreciation which we unconsciously apply to a whole series of acts of the human activity. We declare them good, and consider them as good actions, merely because they have produced in us, in the emo tional regions of our moral sensibility, an impression equivalent to that which a gustatory impression agree ably perceived determines in the sensorium.