PULPS AND SACS OF THE HUMAN TEETH. 



23 



Fig. 22. 



but a longitudinal section showed that the lips only had 

 adhered, the walls had not. The follicle 

 (6, Fig. 22) had become a sac, in conse- 

 quence of which a cavity (&) remained be- 

 tween it and the surface of the gum. Gela- 

 tinous substance had been deposited in the 

 sac (6), and in the neighbourhood of the cavity below it 

 (b), as in the other sacs. 



The lower jaw exhibited changes analogous to those in the 

 upper. 



12. Child at Birth. A longitudinal section was made 

 through the posterior part of the 

 under jaw, when the sacs and pulps 

 of the posterior milk-molar, and of 

 the first permanent molar, and the 

 arrangements represented in Fig. 23, 

 were observed. (5) The sac and 

 Fig. 23. pulp of the posterior milk-molar ; 



(6) the sac and pulp of the first permanent molar ; (&) the 

 cavity marked (b, Fig. 22). 



The sac of the permanent tooth (6) was now almost wholly 

 imbedded in the base of the coronoid process of the jaw. The 

 cavity (b) which was attached to the upper part of the sac of 

 the permanent tooth by its posterior extremity, adhered by its 

 anterior extremity to that point of the gum which was attached 

 to the anterior edge of the base of the coronoid process, so 

 as to drag its surface at that point into a dimple. The cavity 

 (b) was consequently longer than it was at its first formation. 

 The granular substance had wholly disappeared. The 

 interior of the sacs had a villous highly-vascular appearance, 

 like a portion of injected intestinal mucous membrane. The 

 original opening of the sac (6) into the cavity (6) was indicated 

 on its inner surface by an indistinct circular lip. The sacs 



