692 OPERATIONS. 



TUBE FALLING INTO WINDPIPE.— There have been several 

 oases of portions of the tube falling into the windpipe and being 

 successfully extracted. On such an accident occurring, it will often 

 be necessary to make a second opening as low down the neck as 

 possible, in order to facilitate the removal of the offending body. 

 We can perform extraction by means of a long forceps, piece of 

 wire bent into the form of a hook at one end, or other convenient 

 instrument. We may, by compressing the larynx of the animal 

 with a finger and thumb, one on each side, make him cough and 

 thus induce him to project the foreign body above the opening in 

 the windpipe, at which moment an assistant should be ready to 

 insert his finger into the opening, and, preventing in this manner 

 the body from falling back into the lower part of the larynx, to 

 take it out. 



Trephining 



is the boring through of a piece of bone. The operation is almost 

 invariably confined to the bones of the skull or upper jaw, and is 

 employed to give vent to diseased products which have accumulated 

 in the sinuses of the head (p. 373), to relieve pressure on the brain, 

 to facilitate the removal of back teeth, etc. It is most con- 

 veniently performed by means of a trephine, which is a circular 

 saw made for the purpose. The operation is fully described in 

 Peuch and Toussaint's " Chirurgie Veterinaire." 



Twitching. 



The ordinary twitch is a staff about two inches in diameter, two 

 or three feet long, and furnished with a loop of cord which is passed 

 through a hole bored at one end of the stick. The thickness of 

 the cord should not be less than that of the little finger of an 

 ordinary man's hand, and should be made of soft material so as 

 not to cut the horse's skin. The loop should be made large enough 

 to freely admit the hand. 



The best plan for applying the twitch (Fig. 179) is for the 

 operator to pass his right hand through the loop of the cord, grasp 

 the off side of the head collar or halter with the left hand, gently 

 take hold of the muzzle with the right hand, and make over the 

 stick of the twitch to an assistant, who should twist it round 

 steadily, until the animal's muzzle becomes tightly squeezed by 

 the cord. When thus fixed, the horse will generally keep quiet 

 during ordinary operations ; for, if he makes any movement, he 

 will be severely hurt by the twitch. 



This instrument may be easily improvised by placing a loop 

 of cord round the muzzle and tightening it by a stick passed 



