9S6 PHILOSOPHICAL TBANSACTIONS, [aNWO 1742-3. 



placed over- against this cavity, and on a level with its axis, without being able 

 to enter into it, by reason of the firmness and exactness of the powers for re- 

 taining the opposite parts in this state of regular extension ; and in this case 

 there will remain for us, in order to finish the operation, to conduct the head 

 of the bone into its cavity, or to let it go into it : but what shall we do then ? 

 If we slacken the extremity of the lever, or if we lift the same up, we 

 bring the head back to the same place where we took it up ; that is, the luxa- 

 tion to its former state. If we resolve to relax the running knots, the opera- 

 tion will be long, and the patient will have time enough to cry out. 



In order to avoid these inconvenients, M. le Cat mounted the bracer on 

 the lever in a groove, and he stopped it in this state by the teeth of its elastic 

 tail ; by means of this construction, when the surgeon perceives that the bone 

 is over-against its cavity, he directs the assistant, who attends the extremity 

 of the lever, to press upon the handle d, fig. 6, of the elastic tail of the bracer, 

 that the teeth placed under the arch c, near the said handle, may quit their 

 hold, and that the whole bracer, which is now no longer stopped, may slide on 

 the lever towards the patient, and by this means let the head of the bone enter 

 into its cavity. 



The necessity of this management with our ambe, is a demonstration that 

 it is far from having that capital fault, with which M. Petit reproaches the ambe 

 of Hippocrates ; viz. " that it pushes the head of the bone into its cavity, be- 

 fore the extension and counter-extension are made." 



If it be feared that the re-entering of the head of the bone might be too 

 sudden, and occasion a shock, that might hurt the bones, it will be easy to 

 prevent it, by substituting to the stop, into which the teeth of the bracer catch, 

 a toothed wheel a, fig. 5, having in its centre a handle bd; which handle 

 during the operation will be stopped by the iron c, fixed on this piece by the 

 screw p ; the said handle will also stop the teeth e, that catch into the toothed 

 wheel ; and when the bracer is to be loosened, the assistant, who holds the 

 lever with one hand, will take the handle with the other, and having got the 

 screw p taken off, he will remove from the piece c, that stops it, the part db 

 of the handle, by means of its moveable arbor d, so that the handle will come 

 at a right angle, as it is represented by dots : then the assistant's hand, sustain- 

 ing all the effort of the handle and of the bracer, will moderate by the handle 

 the sliding of the bracer, and the entering of the head of the bone into its ca- 

 vity, with all the slowness he shall think proper for this operation. 



Thus much concerning the reduction of a luxation of the arm below, which 

 is the only kind of luxation in which the ambe of Hippocrates can be used. 

 He has succeeded in remedying this defect by the simplest thing in the world. 



