468 BLOOD-VESSELS OF THE TONGUE. 



large branches: one of which, called the Sublingual^ passes 

 under the tongue between the genio-hyo-glossus and the sub- 

 lingual gland, and extends near to the symphysis of the upper 

 jaw ; sending branches to the sublingual gland, to the muscles 

 under the tongue, to the skin, and the lower lip. The other is 

 in the substance of the tongue, on the under side near the sur- 

 face, and extends to the apex. 



The veins of this organ are not so regular as the arteries : 

 they communicate with the external jugular, and some of them 

 are always very conspicuous under the tongue : these are called 

 ranular. 



It is to be observed, that the vessels on each side have but 

 little connexion with each other ; for those of one side may be 

 injected while the others continue empty. 



The tongue is also well supplied with nerves, and derives 

 them from three different sources on each side, namely, from the 

 fifth, the eighth, and ninth pairs of the head. 



The lingual portion of the third branch of the fifth pair pass- 

 ing under the tongue, enters its substance about the middle, and 

 forms many minute branches, which pass to the papillae of the 

 forepart of the tongue. 



The glosso-pharyngeal portion of the eighth pair, sending off 

 several branches in its course, passes to the tongue near its basis, 

 and divides into many small branches, which are spent upon the 

 sides and middle of the root of the tongue, and also upon the 

 large papillae. 



The ninth pair of nerves are principally appropriated to the 

 tongue. They pass on each side to the most fleshy part of it, 

 and after sending one branch to the mylo-hyoideus, and another 

 to communicate with the lingual branch of the fifth pair, they 

 are spent principally upon the genio-glossi, and linguales 

 muscles. 



The tongue answers a threefold purpose. It is the princi- 

 pal organ of taste. It is a very important agent in the articu- 

 lation of words, and it assists in those operations upon our food, 

 which are performed in the mouth. 



