150 THE SENSES. 



May the temperature sense be educated ? 



Yes. For example, a skilled bath-attendant is' able to determine 

 with an astonishing accuracy the temperature of water by immers- 

 ing his hand. 



Does the delicacy of the temperature sense correspond with that 



of touch proper ? 



Yes, in the main, but there are some situations in which the 

 skin is very thin, and the temperature sense is relatively much 

 more delicate than the tactile. 



TASTE. 

 What conditions are necessary for the sense of taste ? 



Aside from the conditions which are always necessapy for sense- 

 perception viz. proper organs for receiving, communicating, and 

 perceiving the sensory impulse there must be present a sapid sub- 

 stance which must be in solution. The solution in the case of dry 

 substances is effected by the saliva. It is also necessary that the 

 surface of the organs of taste shall be moist. 



Where does the sense of taste arise ? 



Chiefly from the tongue, though there is some power to taste 

 resident in the soft palate, fauces, tonsils, and pharynx. In the 

 tongue the taste is more acutely developed in the posterior portion, 

 though in most the tip and sides are sensitive to taste. The cen- 

 tral portion of the dorsuni is not an actively sensitive taste-organ. 

 The under surface of the tongue is little if at all sensitive to taste. 



What nervous supply conducts the taste-sense ? 



Probably the glosso-pharyngeal. The lingual branch of the 

 fifth (or gustatory) is also a conductor of taste-impressions for 

 the front of the tongue. 



Describe, roughly, the tongue. 



The tongue is a flattened muscular organ covered by epithelium. 

 It is controlled by intrinsic and extrinsic muscles, which give it a 

 remarkable flexibility of movement ; the latter for its larger, and 

 the former for its more delicate, actions. 



What kinds of papillae characterize the mucous membrane of the 

 tongue ? 



There are three varieties found, which are known as Jilffomi, 

 fung if orm, and eircwnvaHate papillae. These are set chiefly upon 



