10 T. C. WHITE ON THE SO-CALLED " NERVE" OF THE TOOTH. 



There are great and, I fear, almost insuperable difficulties in tlie 

 way of clearly seeing the termination of the nerve fibres in the 

 pulj) ; one can only conjecture at the method in which they end. 

 In some specimens two fibres may be seen running side by side for 

 some distance, and when you expect to see a loop the ends are 

 found separated ; this may probably arise by the pressure used to 

 render the pulp thin enough for observation. Some specimens, 

 again, show a very apparent looping of the fibres, but the loops 

 extend round the circumference towards the end of the pulp, they 

 are so large ; but in no case have I met with fibres that would lead 

 us to suppose that were they small enough to enter the tubuli 

 that they do so. How, then, are we to account for the painful sen- 

 sation experienced in cutting into live dentine, unless we suppose 

 that a connection of some kind exists between the tubuli and the 

 fibres of the nerve ? The only theory that can be suggested is 

 that the dentinal fibre contained in a tube of the dentine passes out 

 through its odontoblast, and then, becoming fused with the nerve, 

 conveys the sensation to the brain, and we are conscious of the 

 irritation. 



I have not found it possible to see this connection between the 

 odontoblast and the nerve fibres, because the re-agents usually em- 

 ployed to render nerves visible, dissolve away the odontoblasts ; 

 neither have I, by means of thin sections, been more fortunate, as 

 the proximal caudal appendage of the odonto blast is too trans- 

 parent and too minute to admit of demonstration, except, per- 

 haps, by the employment of new re-agents ; in specimens of the 

 pulp, that after staining with carmine have been teased out with 

 needles, the isolated fibres have had, besides their own coloured 

 nuclei, coloured odontoblasts, with this internal caudal appendage 

 fused into their outer parts. Such may be the general mode of 

 their connection, but I am not clear on that point. Such, then, are 

 a few of the principal elements met with in a microscopical examin- 

 ation of what is popularly termed the '■^nerve''' of a tooth, but incase 

 any member present may feel inclined to work out these details for 

 himself, it may be as well to append a few remarks relative to the 

 plans of investigation, attended by the best results. The teeth 

 employed have been temporary teeth, removed in a healthy con- 

 dition, to make room for the advancing permanent set, any others 

 being unsuitable from disease. It is necessary to exercise great 

 care in extracting the pulp from them, as the bone dust from the 



