PULPS AND SACS OF THE HUMAN TEETH. 19 



Upper Jaw. The lobes (t, o, u, Fig. 21) had become 

 highly developed. The anterior one 

 (u) was convex anteriorly, with a 

 sharp edge directed backwards, and 

 corresponded with the incisive teeth. 

 The central lobe (o) had become 

 shorter, but more prominent, like a 

 canine tooth. The posterior (t) had 

 united firmly with the longitudinal 

 lobe all along marked (r), so as to 



close the open portion of the groove (a, Fig. 17), which 

 was described in the two last subjects. The raphe of the 

 groove between these two lobes w T as serrated, and a vessel 

 was seen traversing each denticulation. The raphe then ran 

 close along the inner edges of the bases of the lobes (o and 

 u). The median lobule was triangular, the base posterior ; the 

 apex in front continuous with the labial frenum, and situated 

 between the anterior pointed extremities of the lobules, (u, u). 

 The lateral lobules were very distinct. The other less im- 

 portant changes which had taken place in the palate may be 

 understood by comparing Figs. 21 and 17. 



The membrane of the palate, with the sacs of the teeth, 

 was removed from the bone. The fundus of the follicle (6, 

 Fig. 19), had now assumed the appearance of a sac, and the 

 other ten, instead of being grouped, had become isolated. 

 The branch of the dental artery, which supplied each of the 

 sacs and their pulps, was seen, when it reached the fundus of 

 the former, to give off a number of twigs, which, radiating 

 from their common centre, proceeded perpendicularly towards 

 the gum, near which they inosculated with others proceeding 

 from it. The combined vessels then formed a pretty minute 

 network in the spongy membrane formerly described. 



Transverse sections were now made by the scissors through 

 all the sacs. The general appearance of. these sections was 



