332 



THE HUMAN BODY. 



the subjacent dentine. It is thickest over the free end of the 

 crown, until worn away by use. Covering the enamel in 



FIG. 110. Section through a premolar tooth of the cat still imbedded in its 

 socket. 1, enamel; 2, dentine; 3, cement ; 4, the gum ; 5, the bone of the lower 

 jaw ; c, the pulp-cavity. 



unworn teeth is a thin structureless horny layer, the enamel 

 cuticle. 



The Tongue (Fig. Ill) is a muscular organ covered by 

 mucous membrane, extremely mobile, and endowed not 

 only with a delicate tactile sensibility but with the terminal 

 organs of the special sense .of taste; it is attached by its root 

 to the hyoid bone. On its upper surface are numerous small 



