120 TASTE. 



either side, or to its upper surface close to the tip. Almost 

 all unmixed sensations of taste may be referred to one of 

 four fundamental kinds, viz., bitter, sweet, salty, and acid. 

 Those which cannot be so classified result for the most 

 part from the " blending " of gustatory with tactile or 

 olfactory impressions. Of the four fundamental tastes, 

 all can be appreciated by the papillae vallatae and the 

 papillae foliatae. The tasting power of the tip is im- 

 perfect, and in some persons wanting. When present, 

 it is in most persons confined to the appreciation of acid, 

 sweet and salty tastes. Taste sensations can be excited 

 by the passage of voltaic currents through the base of 

 the tongue, particularly when the anode is applied to 

 the neighbourhood of the papillae vallatae, or to the 

 papilla foliata of either side. Taste is believed to be 

 dependent on the excitation of certain end-organs, the 

 so-called taste buds, which are to be found in the struc- 

 tures above mentioned. As, after section of the glosso- 

 pharyngeal nerve in animals, these organs degenerate and 

 finally disappear, there can be little doubt that they con- 

 tain the gustatory terminations of that nerve. In judging 

 of their function it must remembered that they are met 

 with beyond the limits of the gustatory region, as, e.g., 

 on the under surface of the epiglottis, in the larynx and 

 in the papillae fungiformes of parts of the tongue which 

 are not endowed with taste. 



The taste region at the base of the tongue is supplied 

 by the glossopharyngeal nerve. The tip of the tongue 

 receives its supplies from the lingual, and has been found 

 in several instances in man to lose its tasting power after 

 destruction of that nerve. There is, however, reason for 

 believing that the gustatory fibres of the lingual are ulti- 

 mately derived from the glossopharyngeal nerve, through 

 the tympanic plexus. In animals, after section of the 

 glossopharyngeal nerves, near their origin, taste appears 

 to be entirely absent. 



