THE DENTAL TISSUES. Ill 



I have never seen the fibres, whether in longitudinal or 

 in transverse sections, pass straight in the shortest possible 

 line from the bone to the cementum, but they invariably 

 pursue an oblique course, which probably serves to allow for 

 slight mobility of the tooth without the fibres being stretched 

 or torn. 



The vascular supply of the root membrane is, according 

 to Wedl, derived from three sources ; the gums, the vessels 

 of the bone, and the vessels destined for the pulp of the 

 tooth, the last being the most important. 



The nerve supply also is largely derived from the dental 

 nerves running to the dental pulps ; other filaments come 

 from the inter-alveolar canals (canals in the bone, contain- 

 ing nerves and vessels, which are situated in the septa 

 separating the alveoli of contiguous teeth). 



It should be borne in mind that the tooth pulp and the 

 tissue which becomes the root membrane have sprung from 

 the same source, and were once continuous over the whole 

 base of the pulp. A recognition of this fact makes it easier 

 to realise how it comes about that their vascular and nervous 

 supplies are so nearly identical. 



The human tooth is, accepting as correct the researches 

 of Bodecker, which appear in every way deserving of credence, 

 connected with the living organism very intimately, even 

 though its special tissues are extra-vascular. 



For , blood vessels and nerves enter the tooth pulp in 

 abundance ; the dentine is organically connected with the 

 pulp by the dentinal fibrils ; these are connected with the 

 soft cement corpuscles, which again are brought by their 

 processes into intimate relation with similar bodies in the 

 highly vascular periosteum. 



So that between pulp inside, and periosteum outside, there 

 is a continuous chain of living plasm. 



