Taste. 481 



consequently excited to a high degree of activity. It has therefore be- 

 come highly dilFeivntiuted. The tip of it is the most delicate touch or- 

 gan we have, surpassing even the fingers ; while a part of the rest of 

 the surface is also sensitive to taste impressions. The ultimate organs 



* 



FIG. 221. Human tongue showing the 

 top or Dorsum. 



d. Smooth mucous surface at the root 

 of the tongue, about half an inch long. 



a. Glandular area- 



/.Eight fossulate papillae arranged in 

 chevron form. Sometimes there are ten 

 in man and sometimes only six or four. 

 (After H. H. Walter.) 



of these functions are called pap- 

 illae. The number of the papillae 

 on the surface of the tongue is 

 very great, and they are of three 

 or four different sorts. About a 

 half an inch in length of the root 

 of the tongue is a smooth mucous 

 surface covered with follicles for 

 secreting a mucous fluid which aids 

 in lubricating the food for swal- 

 lowing, like the follicles of the 

 palate lips, &c. In front of this 

 area and arranged in the form of a 

 chevron with its apex pointing in 

 ward, is a row of very large cells, 

 usually eight in number. Each of 

 Fia 221 these is surrounded by a ditch, and 



on that account they are called circumvallate or fossulate papillae ( see 

 fig. 222). 



A second sort of papillae are those called fungiform. They are scat- 

 tered about the top and along the edges of the tongue. They are of a 

 whitish tint and consist of rounded heads on top of short stems like mush- 

 rooms, hence the name fungiform. 



FIG. 222. Section through the Large circumvallate 

 or fossulate Papilla of the Tongue. 



a. Top. 



jo. Pedicle through which the nerves and vessels 

 enter. 



6. Ditch. 



c. Scolloped margin of same. , 



.-Taste buds. 



Fia. 222. 



These and the large circumvallate papillae are the main organs of taste. 

 The third sort of papillae are situated chiefly in the central part of the 

 tongue. They are conical in shape, and are named the pyramidal or 

 filiform papillae. Those of the third species are the most numerous. 



