New Infirumentfor tie TLxtruBion of Teeth. 28 1 



other caufes of rejijlance ; but in mills there is not only fric- 

 tion, but bfiijtacles to be removed : and experiments made on, 

 friction have proved tnat the frictions of many kinds of bodies 

 increafe in direct proportion to their velocity. But the ve- 

 locity of a cvtton-mil! at work may be considered as a me- 

 chanical efted, and, if fo, muft correfpond with its producing 

 caufe. 



XLII. Account of a new Inftrument for the Extraction of 

 Teeth, ly the Inventor, Mr. Rekce, Member of the 

 Royal College of Surgeons, London* 



1 



SIR, Craven-Street, Strand, Aug. 15, iEoi, 



N the firft Number of the fecond Volume of your very ufeful 

 Publication is an account of an iniirument for the extraction 

 of teeth, v. hi. li the inventor (a Mr. Brown> reprefents as a 

 very great improvement of. the German key inltrunv. nts. This 

 great improvement confifls in a deprem\,n on the front of the 

 fulcrum, which (as he obferves) " forms a bed to receive the 

 tooth." The experiments of Mr. Brown, I am well in- 

 formed, were made on an old jaw of a fkeleton, the alveolar 

 proeefs of which being imperfect, the application of the con- 

 caved fulcrum to the convexity of the tooth was eafily ad- 

 mitted ; and, no doubt, its extraction effected u without 

 much violence to the jaw, or pain to the patient. " But in 

 the living Juhjecl, the alveolar proeefs and contiguous loft 

 parts being interpofed between the concaved fulcrum and the 

 tooth, the great advantages derived from this invention are, 

 an unavoidable laceration and contufion of the gum, and great 

 violence to the jaw-bone and focket, producing troublefome 

 inflammation and often alarmi ng hemorrhagies, from there 

 being no corref ponding eminence or the gum, on which it 

 refts, to fill up the hollow (the bed) of the fulcrum : the 

 corners, by the preflTure neceflary for the expulfion of the 

 tooth (which, when firm, is verv confiderable) are produc- 

 tive of verv ferious mifchief; and thofe praeYuioners who 

 were induced to give thefe. instruments a trial, experiencing 

 their bad effects, have returned them to the maker. 



Similar effects (however, in a much lels degree) too often 

 arjfe from the preflureof the heel of the inftrument in common 

 life, and the oblique direction in which the tooth is extracted ; 

 to obviate which I have inventea an inftrument which, by 

 the peculiar curvature of the claw, eltvates the tooth in nearly 



a per-* 



