102 DIGESTION 



alive. When for any reason they are destroyed, tlu 

 tooth is dead; but this does not interfere with its use- 

 fulness, since a dead tooth, if properly cared for, may 

 remain in the jaw for many years. 



Tongue. The tongue, 'which helps to hold and move 

 the food in chewing, consists of a mass of interlacing mus- 

 cular bands, so distributed that they can move the tongue 



Sternomastoid muscle/ 

 Parotid gland and duct' 

 Jugular vein' 

 Carotid artery' 

 Submaxillary gland and duct 



Sublingual gland and duct.' 

 Jaw bone- 

 FIG. 67. The salivary glands, a portion of lower jaw having been removed. 



to any part of the mouth or curl it up so that its tip can 

 reach to all the teeth. The tongue is richly supplied 

 with blood-vessels and nerves, and is covered with a 

 thick membrane, which contains upon its upper surface 

 the organs of taste. 



