THE DENTAL TISSUES. 



67 



way they may be seen stretching across like harp strings 

 between two pieces of dentine, when this is torn by needles, 

 and they can be thus shown in fresh fragments just as well 

 as in those of decalcified dentine. When stretched to a 

 considerable extent their diameter becomes diminished and 

 they finally break, a sort of bead sometimes appearing at the 

 broken end (Tomes). This would seem to indicate that the 

 substance of the fibril is of colloid consistency, and that its 

 external portions are in some degree firmer than its axial 

 portion. 



The dentinal fibrils are well seen in the accompanying 

 figure, in which some hang out from the edge of the dentine, 



FIG. 30 *. 



while others have been pulled out from the dentine and are 

 seen attached to the odontoblast cells. 



The dentinal fibril is capable of being stained with car- 

 mine, though with some difficulty; in young dentine it 

 is more easily stained, especially near the pulp cavity, and 

 the accompanying drawing is taken from such a section of 



(*) Surface of the pulp, with the odontoblast layer in situ. The dentine 

 fibrils pulled out of the dentinal tube hang like a fringe from the odonto- 

 blast layer : dentine fibrils are also seen hanging out from the edge of the 

 dentine, to which, to the right of the figure, a few odontoblasts remain 

 attached. 



F 2 



