VOL. XLII.3 PHILOSOPHICAL TRANSACTIONS. 66\ 



Hence M. le Cat was induced to contrive a new ambe, in which he has en- 

 deavoured to rectify all the defects before mentioned. 



Description of the new u4mbe.-^The basis of the whole machine is an elbow- 

 chair all of solid wood, fig. 3, pi. 15. higher than others usually are, in order 

 to give room to the lever to play the more freely, which cannot be lowered any 

 farther than to the floor on which the elbow-chair stands. To prevent any 

 uneasiness to the patient from that height of the chair, it has a foot-stool that 

 makes part of the chair, and brings the seat to its usual height. 



Each arm of the chair is pierced with a round hole, to receive the stem or 

 foot of the ambe. If the luxation be on the right side, the foot is run through 

 on the same side; and vice versa. The patient is tied partly to the back of the 

 chair, partly to a piece joined to the chair on that side where the ambe is 

 placed. This solid union of all the pieces of the machine among themselves, 

 and with regard to the patient, furnish its action with all the force and certainty 

 possible. The ambe of Hippocrates can play but to a small extent : it is sepa- 

 rate from the chair in which the patient sits, and he is left to the care of the 

 assistants ; all disadvantageous circumstances, which are remedied by the new 

 machine. 



In that of Hippocrates, the body of the patient has no other support against 

 the extension of the lever than the very vertical piece, fig. 4, on which the 

 lever rests ; this piece is narrow, has no proportion, or no union with the figure 

 of the body to which it is applied, and consequently must change his position 

 on that piece on the least effort the patient makes. 



The foot of M. le Cat's lever has no connexion with the patient's body : there 

 is between the foot and his body a particular piece called the bodice, represented 

 in fig. 1 , pi. 1 6, made to fit itself to the body ; and in order to render that applica- 

 tion easy, the part which touches the body is quilted. This bodice is fixed to the 

 arm of the chair between 1 large iron cheeks, a, b, fig. 3, pi. 1 5, by 2 strong iron 

 pins, which run through them, and are stopped at their extremities with nuts 

 screwed on. The concave part of this piece, where the body enters, is placed 

 perpendicularly under the end of the lever, yet so that the lever be a little far- 

 ther advanced towards the patient, than the bottom of the bodice, that the lever 

 may thrust itself the better in under the arm-pit. As there are cases where the 

 head of the lever ought to be very short, or very near the point it rests on, and 

 others again on the contrary, where that extremity of the lever ought to be 

 longer, and farther off the point of its rest, the bodice of course ought to be 

 set more backward or forward, as the end of the lever is, the direction of whicli 

 it follows every where. For this reason 2 rows of holes are contrived along 

 the sides of the bodice, 'and between these 2 sides a notch is cut out, to make 



