216 MICROSCOPIC ANATOMY OF THE TEETH 



purple coloration, the ' end cells ' are not visible. In these 

 sections the ' end cells ' are a deep black and the odontoblast 

 cells and their processes are only very faintly stained a pur- 

 plish brown, but the dentinal fibril is in many parts distinctly 

 traceable into the dentinal tube and the beaded black nerve 

 fibre is seen passing in with it (fig. 129). 



The photographs from which the accompanying figures 

 were taken were mostly from parts of the sections where 

 the pulp was slightly separated from the dentine, as these 



FIG. 131. Nerve-end cells with their axon processes passing to the den- 

 tine (d). The beaded fibre on the left under strong tension. ( x 800.) 



show more clearly the relations of the nerves to the odonto- 

 blasts and their processes the fibrils. They also show clear 

 evidence of the great extensibility of the neurofibrils, and 

 exhibit with great distinctness their characteristic beading. 

 It can be seen in fig. 130 that when the pulp is in contact 

 with the dentine, the axon of the ' end cell ' has a wavy or 

 undulating course, but when the pulp is partially pulled 

 away the fibres become straightened out, and if the separa- 

 tion is very wide they are further pulled out of the tubules 

 of the dentine and are seen as strands of great tenuity. 

 These eventually part asunder as seen in fig. 131, but they 



