Experimental physiology / by Sir Edward Sharpey-Schafer.

  • Edward Albert Sharpey-Schäfer
Date:
1921
Catalogue details

Licence: In copyright

Credit: Experimental physiology / by Sir Edward Sharpey-Schafer. Source: Wellcome Collection.

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    Taste and Smell Taste.—(a) To test the localisation of taste, direct the subject to close his eyes and put out his tongue. This organ is then dried, and different parts' are touched with a small brush or a glass rod moistened with the sapid substance in solution. After each observation the mouth must be rinsed with water. The following solutions may be used for testing the four qualities of taste, t. I | | I | ! | I I I I | I i I I | II II | I I I I j M I 1 I $cr. Fig. 90.- screen Zwaardemaker’s olfactometer, n, nose-piece; scr, t, porous tube sliding over graduated glass tube. viz. : for bitter, 1 per cent, solution of quinine sul- phate ; for sweet, 5 per cent, solu- tion of sugar; for acid, 2 per cent, solution of citric acid; and for salt, 5 per cent, solution of common salt. Xotice the time which intervenes between the appli- cation of the sapid substance and its effect. Record your results as regards localisation upon an outline plan of the tongue. (b) Test different parts of the tongue by applying closely-set electrodes arranged to conduct a weak faradising current. (c) Chew a leaf of Gymnema sylvestris, or paint the tongue with cocaine solution, and determine whether the taste of any of the varieties of sapid substances is affected. Smell.—The sense of smell is tested by Zwaardemaker’s olfactometer, which consists of a glass tube with one end adapted to the nostril, while over the other end a tube constructed of, or impregnated with, the odoriferous substance slides, so that a greater or less amount of its inner surface can be exposed to the air which is passing through the glass tube into the nostril (Fig 90). I3t
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