en. LIIL] 



VARIETIES OF TASTE 



733 



striking contrast to the sense of smell ; flavours are really odours. 

 In testing the sense of taste in a patient, the tongue should be 



protruded, and drops of the 

 . L X*~~~ /- substance to be tasted ap- 



X fC ^&^^ P^ ec * w ^ a came l' s hair 



\ ij /^^5>-^^ / brush to the different parts ; 

 ^t^^^^/y^ tne subject of the experi- 

 ment must signify his sen- 

 sations by signs, for if he 



FIG. 534. Taste-bud from dog's epiglottis 

 (laryngeal surface near the base), precisely 

 similar in structure to those found in 

 the tongue, a, Depression in epithelium 

 over bud ; below the letter are seen the 

 fine hair-like processes in which the cells 

 terminate; c, two nuclei of the axial 

 (gustatory) cells. The more superficial 

 nuclei belong to the superficial (encasing) 

 cells ; the converging linos indicate the 

 fusiform shape of the encasing cells, x 400. 

 (Schofield.) 



FIG. 533. Filiform papillas, one with epithelium, 

 the other without. %*-. p, The substance of the 

 papillae dividing at their upper extremities into 

 secondary papillae ; a, artery, and v, vein, dividing 

 into capillary loops ; c, epithelial covering, lamin- 

 ated between the papillae, but extended into hair- 

 like processes, /, from the extremities of the 

 secondary papillae. (From Kolliker, after Todd 

 and Bowman.) 



withdraws the tongue to 

 speak, the material gets 

 widely spread. The more 

 concentrated the solution, 

 and the larger the surface 

 acted on, the more intense 

 is the taste; some tastes are perceived more rapidly than others, 

 saline tastes the most rapidly of all. The best temperature of the 

 substance to be tasted is from 10 to 35 C. Very high or very low 

 temperatures deaden the sense. 



Individual papillae, when thus treated with various solutions, show 

 great diversity: from some only one or two tastes can be evoked, 

 from others all four. The papillae may also be stimulated electrically. 

 It is possible by chewing the leaves of an Indian plant (Gymnema 

 sylvestre) to do away with the power of tasting bitters and sweets, 

 while the taste for acids and salts remains. 



