[ 4*>i D 
will alfo flop the Teethe, which catch into the tooth'd 
Wheel ; and when the Bracer is to be loofened, the Af- 
ftftant, who holds the Lever with one Hand, will take 
the Handle with the other, and having got the Skrew 
F taken off, he will remove from the Piece C, that 
flops it, the Part T), of the Handle, by the means 
of its moveable Arbor *D, fo that the Handle will 
come at a Right Angle, as it is reprefented by Dots: 
Then the Afliftant’s Hand, fuftaining all the Effort of 
the Handle and of the Bracer, will moderate by the 
Handle the Aiding of the Bracer, and the entering of 
the Head of the Bone into its Cavity, with all the 
Slownefs he fliall think proper for this Operation. 
Thus much concerning the Reduction of a Luxa- 
tion of the Arm below ; it is known, that this is the 
only fort of Luxation in which the Ambe of Hippo - 
crates can be made ufe of (the fecond DefeCt ob- 
ferved by M. Betit in this Machine). 1 have fuc- 
ceeded in remedying againft thisDefed by the flmpleft 
thing in the World, 'viz. by giving to the Foot that 
enters into the Arm of the Chair a cylindrical Shape, 
by which means it is able to turn all manner of ways; 
fo that if the Luxation is forwards, one only needs 
turn the Extremity of the Lever accordingly, lower- 
ing it at the fame time enough to make the neceflary 
Extenfion and Elevation ; by this Turn of the Extre- 
mity of the Lever forwards, the Head of the Bone is 
of neceflity carried backwards, and replaced into its 
Cavity. One eafily conceives, that one mull go to 
work in the oppoftte way, when the Luxation is 
backwards, and fo on as for the reft; all according 
to the Directions of the Surgeon placed at the Arti- 
culation, who is to be attentive to examine the State 
of 
