io8 



OPERATIVE TECHNIQUE. 



still divided on the point, and as many practitioners appear to 

 place faith in the operation, a diagram is furnished below show- 

 ing the position in which setons are introduced for various con- 

 ditions. Setons are inserted with a special needle (Fig. 136), from 

 eight to sixteen inches in length, and usually made of steel or 

 soft iron. The point is spatulate and of steel, the body is usually 

 flattened and often divided into two parts, which can be screwed 

 together. The eye is sometimes at one end, sometimes at the other. 

 For the purpose of passing frog setons Sewell invented a special 

 needle (Fig. 136A). For operating on ha;matomata, etc., the 

 needle shown in Fig. 136B is used. It consists of two cylindrical 



Fig. 135. — Schema showing positions in which setons may be inserted. 



portions about three sixteenths of an inch in thickness, which can 

 be screwed together. The point resembles a three-sided pyramid. 



Should the animal prove ver}' troublesome it may require to be 

 cast before a seton can be inserted, but as a rule it is sufficient to 

 apply a twitch and lift one of the fore-feet. Speaking broadly, it 

 is best to pass the needle from below upwards, as should the 

 animal struggle it is more easily withdrawn, while it is less likely 

 to go astray. Should it be inserted in the opposite direction- and 

 an error be made necessitating change of direction, a pocket is 

 left in which pus may accumulate. 



Views differ as to the depth to which setons should be inserted. 

 Some prefer the subcutaneous tissue, others penetrate beneath the 



