98 TOMES, ON THE DENTAL TISSUES. 



It has been stated that, closely applied to the surface, a 

 cellular mass will be found, and that this is but sliglitly 

 adherent, the wasting and growing surfaces readily parting, 

 unless the two are held together by the irregularities on the 

 surface of the former. It will sometimes happen that the 

 cellular mass penetrates into the dentine through a small open- 

 ing, and there dilates, in which case its withdrawal becomes 

 impossible. This condition is now and then found on sec- 

 tions prepared for the microscope, when we liave an oppor- 

 tunity of examining the two tissues in situ. Indeed we shall 

 find a few cells adherent to the surface of the dentine where 

 less deep burrowing has occurred. The cells themselves do 

 not present any peculiarity by which they could be readily 

 recognised, if separated from the part undergoing removal. 

 They are small granular cells, of a more or less spherical 

 form. If a tooth which has lost its fang be carefully re- 

 moved, we shall find remaining in its place a growing fajnlJa, 

 corresponding exactly in size and form to the surface from 

 which it has been separated ; and this separation may often 

 be effected with so little injury to the absorbent organ, that 

 no blood appears upon its surface after the operation, although 

 the organ is highly vascular and readily torn.* The superficial 

 extent of the papilla will be equal to that part of the tooth 

 undergoing waste, but the extent, as regards depth, is slight, 

 for, as the root of the tooth disappears, the socket is con- 

 tracted by the deposition of bone, which forms at the base of 

 the absorbent organ as rapidly as the cellular surface en- 

 croaches upon the tooth. The cases in which we find an 

 exception to this condition are those in which the permanent has 

 advanced close to the fangs of the temporary tooth, when the 

 crypt containing the one communicates with the socket of the 

 other, the rate of growth of the permanent having been greater 

 than the absorption of the deciduous organ ; but even in these 

 cases we may generally observe some part in which the con- 

 traction of the socket is coincident with the absorption of the 

 occupant fang. From the following quotation, it does not 

 appear that Mr. Bell observed these conditions : — 



" It has been ah'eady stated, that the permanent teeth during their 

 formation are crowded together in the jaw, hy being placed in a smaller 

 arch than they would occupy if regularly placed side by side. As the 

 latter, however, is their destined situation, we find that as soon as they 

 are advanced to a certain point of their formation, and can no longer be 

 contained within the alveoli, absoi'ption takes place in the anterior parietes 



* Laforgiie and Bourdct recognised the presence of the absorbent organ, 

 but sujiposed it exhaled a fluid capable of dissolving the roots of the 

 teni])orary tooth. 



