MECHANISM OF GUSTATION. 247 



sense of taste as exist usually in different individuals, it 

 must be difficult to describe with accuracy delicate shades 

 of savor, particularly in alimentary substances ; but the dis- 

 tinct impressions of acidity or bitter quality are easily rec- 

 ognizable. From the observations just cited, it would ap- 

 pear that saline, acid, and styptic tastes are best appreciated 

 through the chorda tympani, and that sweet, alkaline, bitter, 

 and metallic impressions are received mainly by the glosso- 

 pharyngeal. 



Mechanism of Gustation. The mode in which sapid sub- 

 stances are brought in contact with the organ of taste is so 

 simple, that we need only allude to it, before we study the 

 anatomy of the parts directly concerned, and their connec- 

 tions with the terminal filaments of the gustatory nerves. 

 In the first place, the articles which make the special impres- 

 sion are in solution ; introduced into the mouth, they increase 



of the tongue, but which are appreciated, to a high degree, at its posterior por- 

 tion. 



a. Caustic and acid (mineral acids, etc.). 



b. Metallic (sulphate of iron, alum, etc.). 



c. Alkaline. 



d. Ammoniacal, urinous. 



e. Acrid (jalap, worm-seed, onions, garlics, etc.). 

 /. Bitter (colocynth, quinine, aloes). 



g. Putrid. 



" C. Savors appreciated in one way by the chorda tympani, and in another 

 by the glosso-pharyngeal. 



At the anterior part of the At the posterior part of the 



Different Articles. tongue. tongue. 



a. Chloride of potassium. Taste, cool, salt. Sweetish. 



b. Acetate of potash. " burning, acid, pi- Bitter, nauseous, neither 



quant. acrid nor piquant. 



c. Nitrate of potash. " cool, piquant. Bitter, insipid. 



d. Alum. " acid, cool, styptic. Sweetish, not acid. 



e. Sulphate of soda. " salt. Bitter. 



/. Acetate of lead. " cool, piquant, styp- Saccharine. 



tic. 



g. Oxalic acid. " piquant. Bitter. 



h. Bisulphate of quinine. " piquant, acid, cool. Very bitter." 



