SENSE ORGANS. 



I97 



parts of the tongue, but more and more toward the tip. 

 (2) The glosso-pharyngeal (Fig. 33, ?). This also is dis- 

 tributed to all parts, but mainly to the back part and 



adjacent parts of the throat. 

 This is supposed to be the 

 special nerve of taste. (3) 



t.h. 



Fig. 126. — A fungiform papilla, showing the taste bulbs (ti) of a rabbit : 

 A 1 magnified ; B, highly magnified. (After Tuckerman.) 



The hypoglossal (Fig. 33, 12). This is a motor nerve, and 

 presides over the movements of the tongue. Through 

 these three it becomes a tactile organ, a tasting organ, 

 and a talking organ. The manner in which the nerves 

 terminate in the taste papillae is shown in Fig. 125. The 

 flat fungoid papilla are eminently adapted by shape to 

 retain liquids in contact with the taste bulbs. 



COMPARATIVE PHYSIOLOGY OF TASTE. 



There are only two ways in which we can judge of 

 the keenness of taste in lower animals, viz., by the or- 

 ganization of the tongue — i. e., its softness, and espe- 

 cially the development of its papillae, and by observation 

 of the habits of the animal. Judging in these ways, 

 there is probably little difference in this regard between 

 man and mammals. The main difference is that man 

 much more than mammals takes food for the enjoyment 



