100 



OPERATIVE TECHNIQUE. 



H H^, H H^, which are provided with teeth controlled b}- the two 

 spring pawls BB. By slightl}' depressing the handle GG on either 

 side, one of these rods is drawn forward a tooth and immediately 

 secured by its corresponding pawl, wdien it becomes the fixed point 

 through the medium of which the opposite rod is drawn downw^ards. 

 The lower ends of the two rods thus act alternately as fixed points on 

 which the handle G G swings. Reference to the figures will show that 

 movement of this handle in the method described will cause the rods 

 gradually to descend, drawing the loop of the ecraseur A" within the 

 tube C, and slowly dividing any tissue enclosed within the loop K. 

 In later ecraseurs, such as Fig. 113, the movement is effected by a screw. 

 At Professor Dewar"s request Messrs. Arnold have produced an 

 ecraseur with a particularly neat and effective catch b}' means of which 

 the screw can be thrown into and out of action very readil}'. When 

 the catch is in the position marked "free" the "slack" of the chain 



LOCKED 



Fig. 113. — Professor Dewar's ecraseur. 



can be taken up so that the instrument is ready to commence cutting 

 as soon as put in operation. By slipping back the catch the chain 

 becomes locked to the screw, and the apparatus is read}' for use. 

 The screw movement is much preferable to the rack originally fitted in 

 the Chassaignac instrument. The instrument is long enough for the 

 castration of mares and cows in the standing position, and as the 

 chain is bevelled on one edge it crushes through instead of cutting the 

 tissues, thus avoiding a frequent cause of post-operative haemorrhage. 

 On the other hand it may be reversed if \-ery fibrous tissues require 

 to be divided. 



Small and even medium-sized vessels ma}- be divided in this way 

 without_ bleeding. The actionjleiy)ends to 3i).meexte oa.ihe rapidit}- 

 yifhwhi£:h the process. is. carried out. The slower the n-fcjvement the 

 Ifess the bleeding. .For this reason very vascular tissuegj should be 

 v]er}' slowly divjded, and pauses should.-occasionally be ma.i^ ; between 

 each movement bl th!e:ha-n"dles, or eacti complete rotation! of the screw. 







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