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LESSON XXXIV. 

 THE TONGUE AND TASTE. THE NOSE AND SMELL. 



THE tongue is a muscular organ covered with mucous membrane. 

 It is attached by means of muscles to the lower jaw, and is also 

 connected behind with the hyoid bone. 



The organ of taste is the mucous membrane of the tongue, 

 especially that at the upper and back surface, and also the mucous 

 membrane of the posterior 

 portion of the palate. 



On the under surface of 

 the tongue the mucous mem- 

 brane is smooth and thin, 

 like that of the walls of the 

 mouth generally ; but its 

 upper surface is rendered 

 rough and sensitive to taste 

 by a number of papillae which 

 are richly supplied with nerve 

 terminations. 



The papillae of the tongue 

 are large compared with those 

 of the dermis ; they are also 

 quite distinct from each other. 

 The smallest and most nu- 

 merous of these are conical 

 or cylindrical in shape, and 

 are called filiform (Lzk.filum, 

 a thread). Mixed with these 

 are a number of larger papillae 

 called fungiform (Lat. fungus, 

 a mushroom) on account of 

 their resemblance in form to 

 certain of the fungi. They 

 each consist of a round and 

 broad extremity supported on 

 a narrower stalk, and are 

 easily distinguished from the others by their deep red colour. 

 At the back of the tongue there are from seven to twelve very 

 large papillae arranged in two rows obliquely, so as to form the 

 letter V with the point turned backwards. These are termed 





