378 THE TONGUE OK ORGAN OF TASTE. 



The anatomy of the tongue (Figs. 86, 87, 88, 90, 91,) 

 has been given under the head of " organs of deglutition/' 

 It was there stated to he very complex in its structure, and 

 to perform a variety of functions ; composed of no less than 

 ten muscles, by which it can be moved in every possible 

 direction. It is most efficient in the first stages of digestion, 

 and is moreover, in man, the great instrument of speech. It 

 has no less than six large nerves, by which it is endowed both 

 with general and special sensation, i. e. the general sense of 

 feeling and the special sense of taste. Grlands likewise enter 

 into its composition, an immense number of blood-vessels 

 ramify throughout its substance, and the whole is covered 

 by mucous membrane; so that the tongue is one of the most 

 complex and highly organized portions of the body. 



The papillary membrane of the tongue is regarded as the 

 especial seat of taste, and is the only portion of its struc- 

 ture requiring any remarks in this place, in addition to 

 what has already been given. This papillary or gustatory 

 membrane has the closest analogy with the skin, and is 

 considered as possessing essentially the same elements. Its 

 cliorion or cutis-vera is as dense as any part of the skin, and 

 has a large number of muscular fibres inserted into it, by 

 means of which its papillae can be brought readily into 

 contact with every portion of food ; and thus this muscular 

 appendage to the papillary membrane is regarded as play- 

 ing an essential part in the function of taste. Its papillae 

 are like those of the skin, but larger and much more de- 

 veloped. Its rete mucosum has the same indistinctness, 

 Its epithelium is distinctly shown, and has received the 

 name ofperiglottis, having in some animals the consistence 

 of horn. 



The epithelium of the tongue can be removed by macera- 

 tion and by certain inflammatory diseases, and is found to 

 have an arrangement precisely like the epidermis of the 

 skin, and to form a sheath of protection to the several pa- 

 pillae upon its surface. These papillae are very numerous, 

 and were stated to have various names according to their 

 size and shape, as the po.pillce maximce, medice, fungiformes } 



