298 BEP0ET8 lEOM THE SECTIONS. 



TRANSVEESE SECTION OF EANG OF HUMAN 

 TOOTH, SHOWINa CA-SE OF EXOSTOSIS. 



By Me. Huan Pateeson. 



[^Sead before the Microscopical Section of the 'Royal Society of N. S. W.^ 



20 September, 1876.] 



The fangs of the teeth are, under ordinary circumstances, 

 covered on tlie external surface with a thin layer of cementum, 

 but when, whether from caries or any other cause, irritation of 

 the dental periosteum takes place, it gives rise — in some constitu- 

 tions — to the morbid growth termed exostosis, if the word may 

 be allow^ed to pass muster, as strictly speaking it is the cementum, 

 a modified form of bone, which is here enlarged. 



" Mr. Jones, who has made careful microscopical examinations 

 of this substance, describes it as being similar to osseous tissue, its 

 structure being composed of minute granules closely united, 

 tlie individual granules being about the to^-o of an inch in 

 diameter. Scattered through, the so-formed tissue are cells from 

 which numerous tortuous tubes proceed, the tubes themselves 

 freely anastomosing witb eacb other and with those sent from 

 neighbouring cells ; by this arrangement a network of cells and 

 tubes, permeable by fluids, is carried throughout the whole mass. 

 "When the cement exists in any quantity it is traversed by canals 

 for blood-vessels." 



The interest attached to this disease is mainly due to the 

 derangement it may cause to the nervous system. In my younger 

 days, when in London, I had occasion to remove some eighteen 

 teeth and stumps, all more or less affected by exostosis, before 

 permanent relief was afforded. 



Another case which may be of interest to this Section, on 

 account of the name of the sufferer, was that of the late Rev. 

 Wm. Quekett, brother of the late Professor John Quekett, whose 

 labours as a pioneer in microscopical researcb are well known 

 and respected. The offending tooth in this case was an upper 

 molar ; it caused great and long continued suffering, and the 

 exostosis was of a very extensive nature. 



This tooth is in the Hunterian Museum of the Royal College 

 of Surgeons of London. I remember that at the time it impressed 

 me as bearing some distant resemblance to a rustic garden stool, 

 BO nodulated and distorted irere the fangs by the hypertrophy of 

 the cementum. 



