SENSE OF TASTE. 739 



quinine, sugar, common salt, and diluted phosphoric acid. A small brush, 

 about one-third of an inch square, was applied to the surface of the tongue. 

 On being applied, au electrical current was made, which was broken by a 

 movement of the hand as soon as the taste was perceived. When the tip 

 of the tongue was thus excited, the following times were obtained : Com- 

 mon salt, 0.1598 sec.; sugar, 0.1639; phosphoric acid, 0.1676; quinine, 

 0.2351. 



603. The impressions made upon our consciousness by a large proportion 

 of sapid substances are of a complex kind ; being in part derived from their 

 odorous emanations, of which we take cognizance through the organ of 

 Smell. Of this any one may convince himself by closing the nostrils, and 

 inspiring and expiring through the mouth only, whilst holding in the mouth, 

 or even rubbing between the tongue and the palate, some aromatic sub- 

 stance; for its taste is then scarcely recognized, although it is immediately 

 perceived when its effluvia are drawn into the nose. It is well known, too, 

 that when the sensibility of the Schneiderian membrane is blunted by in- 

 flammation (as in an ordinary " cold in the head"), the power of distin- 

 guishing flavors is very much diminished. In fact, some physiologists are of 

 opinion that all our knowledge of the flavor of sapid substances is received 

 through the Smell ; but this, as already shown, would not be a correct state- 

 ment ; and there are cases on record in which the sense of Smell has been 

 entirely lost, without any impairment of the true sense of Taste. 1 



604. Taken in its ordinary composite acceptation, the sense of Taste has 

 for its object to direct us in the choice of food, and to excite the flow of mu- 

 cus and saliva, which are destined to aid in the preparation of the food for 

 Digestion. Among the lower animals, the instinctive perceptions connected 

 with this sense are much more remarkable than our own; thus an omnivor- 

 ous Monkey will seldom touch fruits of a poisonous character, although their 

 taste maybe agreeable; and animals whose diet is restricted to some one 

 kind of food will decidedly reject all others. As a general rule it may be 

 stated, that substances of which the taste is agreeable to us are useful in our 

 nutrition, and vice versa; 2 but there are many signal exceptions to this. Like 



1 An interesting case of this kind, occurring in a Negro who had gradually lost the 

 characteristic hue of his skin, and had acquired the fair complexion of a European, 

 has been put on record by Dr. J. C. Hutchinson. The Olfactory nerve seemed to be 

 entirely paralyzed, whilst the branches of the Fifth Pair retained their integrity ; so 

 that, whilst the proper sense of Smell was entirely lost, a punsjent burning sensation 

 was excited by irritating vapors, and the application of snuff induced sneezing. Not- 

 withstanding this deficiency, the sense of Taste, properly so called, did not seem to be 

 impaired ; for substances which possessed neither odor nor pungency could readily be 

 discriminated, even though their tastes were not widely different. (See Amer. Journ. 

 of Med. Sci., Jan. 1852.) 



2 It is justly remarked by Sir H. Holland (Medical Notes and Reflections, p. 85) 

 that, "In the majority of instances of actual illness, provided the real feelings of 

 the patient can be certainly ascertained, his desires as to food and drink may be safely 

 complied with. But undoubtedly much care is needful that we be not deceived as to 

 the state of the appetite, by what is merely habit or wrong impression on the part of 

 the patient, or the effect of the solicitation of others. This class of sensations is more 

 nurtured out of the course of nature, than are those which relate to the temperature 

 of the body. The mind becomes much more deeply engaged with them ; and though 

 in acute illness they are generally submitted again to the natural law, there are many 

 lesser cases where enough remains of the leaven of habit to render every precaution 

 needful. With such precautions, however, which every physician who can take 

 schooling from experience will employ, the stomach of the patient becomes a valua- 

 ble guide ; whether it dictate abstinence from a recurrence of food ; whether much or 

 little in quantity ; whether what is solid or liquid; whether much drink or little; 

 whether things warm or cold; whether sweet, acid, or saline; whether bland or 

 stimulating to the taste." Further, Sir H. Holland remarks: " It is not wholly para- 



