PHYSIOLOGICAL ANATOMY OF THE ORGANS OF TASTE 643 



Fig. 160. Medium-sized circum- 

 v allate papilla, X 20 (Sappey). 



i, papilla, the base only being 

 apparent (it is seen that the base is 

 covered with secondary papillae) ; 

 2, groove between the papilla and 

 the surrounding wall ; 3, 3, wall of 

 the papilla. 



of saliva, the actual contact of the savory articles is rapidly effected. 



The thorough distribution of these substances over the tongue and the 



mucous membrane of the general buccal 

 cavity leads to some confusion in the appre- 

 ciation of the special impressions ; and in 

 order to ascertain if different portions of the 

 membrane possess different properties, it is 

 necessary to make careful experiments, limit- 

 ing the points of contact as exactly as possi- 

 ble. This has been done, with the result of 

 showing that the true gustatory organ is quite 

 restricted in its extent. 



It has been found that certain gustatory 

 impressions attack readily the parts supplied 

 by the chorda tympani, while others attack 

 the terminal filaments of the glosso-pharyn- 

 geal. Classifying savors as sweets, acids, 

 bitters and salines, 

 it appears that 



sweets attack especially the tip of the tongue ; 



acids and salines, the sides of the tongue ; 



bitters, the back of the tongue. It is said that 



an acid taste may be recognized in a solution 



equivalent to one part of sulphuric acid in one 



thousand of water. Chewing the leaves of 



the gymnema sylvestre abolishes for a time 



the sense of bitters and sweets, but sensibility 



to acids and salines remains. This plant is 



used by the natives in India as a remedy for 



snake-bite. 



Physiological Anatomy of the Organs of 



Taste. Anatomical and physiological re- 

 searches have shown that, at least in the 



human subject, the organ of taste probably 



is confined to the dorsal surface of the 



tongue and the lateral portion of the soft 



palate. The upper surface of the tongue 



presents a large number of special papillae, 



called in contradistinction to the filiform 



papillae, fungiform and circumvallate. These 



are not found on its under surface or anywhere except on the supe- 

 rior portion ; and it is now well established that the circumvallate and 



Fig. 161. Fungiform, filiform, 

 and hemispherical papilla, X 20 

 (Sappey). 



I, i, two fungiform papillae cov- 

 ered with secondary papillae ; 2, 2, 

 2, filiform papillae; 3, a filiform pa- 

 pilla, the prolongations of which 

 are turned outward ; 4, a filiform 

 papilla with vertical prolongations ; 

 5, 5, small filiform papillse with the 

 prolongations turned inward ; 6, 6, 

 filiform papillae with striations at 

 their bases ; 7, 7, hemispherical pa- 

 pillae, slightly apparent, situated 

 between the fungiform and the 

 filiform papillae. 



