THE MOUTH 



133 



Note. The perception of bitter substances is plainer in the posterior 

 portion, while sweet, sour, and salty substances are more quickly recognized 

 in the anterior part and at the borders. The nerves of taste are in the papillae. 



Some elevations of mucous membrane on either side of the base of the 

 tongue form the lingual tonsils. (These are seen only with the aid of the 

 laryngoscope.) They contain lymphoid tissue. 



Parotid 

 gland 



Floor of mouth and sub- , 



maxillary duct / \M\MY\ ^ . Hyoid bone 



Submaxillary gland 



(main portion is drawn backward) 



FIG. 101. SALIVARY GLANDS AND PAPILLA OF TONGUE. (Morris.) 



The mouth opens at the back into the pharynx, through the 

 passage called the isthmus of the fauces. This passage is bounded by 

 two folds on each side running downward from the soft palate and 

 called the palatine arches, or pillars of the fauces. Between the anter- 

 ior and posterior arch of either side is the palatine tonsil, 1 a gland- 

 like body the use of which is not clearly understood 2 (Fig. 100). 



It presents small openings upon its surface leading into recesses or crypts 

 which are surrounded by the follicles of the tonsils. 



Clinical note. Follicular tonsillitis is an inflammation of the mucous 

 membrane and follicles in the crypts. 



1 Feudal tonsil. 



1 The student may see all of these structures by examining her own mouth with 

 the aid of a hand-mirror and a good light. 



