255 



the membrane of the nose, alters its tissue, dries its nerves, and, in the 

 course of time, impairs their sensibility. 



The shortness of the distance between the origin of the olfactory 

 nerves, in the brain, and their termination in the nasal fossae, render 

 very prompt and easy the transmission of the impressions which they 

 experience. This vicinity to the brain, induces us to apply to those 

 nerves, stimulants calculated to rouse the sensibility, when life is sus- 

 pended, as in fainting and asphyxia. The sympathetic connexions, be- 

 tween the pituitary membrane and the diaphragm, account for the good 

 effects of sternutatories, in cases of apparent death. 



CXXVII. Of flavours. Flavours are no less varied and no less nume- 

 rous than odours; and it is as difficult to reduce them to general classes 

 connected by analogies and including the whole*. Besides, there exists 

 no element of flavour, any more than an odoriferous principle. The 

 flavour of fruits alters as they ripen, and appears to depend on the 

 inward composition of bodies, on their peculiar nature, rather than on 

 the form of their molecules, since crystals of the same figure, but belong- 

 ing to different salts, do not produce similar sensations. 



To affect the organ of taste, a body should be soluble at the ordinary 

 temperature of the saliva; all insoluble substances are insipid, and one 

 might apply to the organ of taste, this celebrated axiom in chemistry, 

 corpora non agunt nisi soluta. If there is a complete absence of saliva, 

 and if the body that is chewed is altogether without moisture, it will 

 affect the parched tongue, only by its tactile, and not at all by its gusta- 

 tory qualities. The substances which have most flavour, are those which 

 yield most readily to chemical combinations and decompositions, as acids, 

 alkalies, and neutral salts. When, in affections of the digestive organs, 

 the tongue is covered with a mucous or whitish fur, or of yellowish or 

 bilious colour, we have only incorrect ideas of flavours; the thinner or 

 thicker coating prevents the immediate contact of the sapid particles; 

 when they act, besides, on the nervous papillae, the impression which 

 they produce is lost in that occasioned by the morbid contents of the 

 stomach: hence every aliment appears bitter, while the bilious disposi- 

 tion exists, and insipid, in those diseases in which the mucous elements 

 prevail. 



CXXVIII. Of tlie sense of taste. No sense is so much akin to lhat of 

 the touch, or resembles it more. The surface of the organ of taste differs 

 from the common integuments, only in this respect, that the chorion, the 

 mucous body, and the epidermis which envelope the fleshy part of the 

 tongue are softer, thinner, and receive a greater quantity of nerves and 

 vessels, and are habitually moistened by the saliva and by the mucus, se- 

 creted by the mucous glands contaitied'in their substances. These mu- 

 cous cryptas, and the nerves of the cutaneous covering of the tongue, raise 

 the very thin epidermis which covers its upper surface, and form a num- 



* This has been attempted, though with indifferent success, by Boerhaave, Haller, 

 and Linnaus. Acid, s-weet, bitter, acrid, saltish, alkaline, vinous, spirituous, aromatic, and 

 acerb, were the terms employed by those physicians, to express the general characters 

 of flavours. 



The flavour of any substance appears chiefly to arise from the odoriferous particles 

 which escape from it, during the process of mastication and deglutition, through the 

 posterior nares, and aftect the olfactory nerves in that situation. Authors Note, 



