690 OPERATIONS. 



by means of a twitch, reduce the sensibility of the part by injecting 

 cocaine (p. 608), get his head elevated by an assistant, render the 

 ■skin tense over the part by means of a finger and the thumb 

 of the left hand, make in the middle line of the throat a longi- 

 tudinal incision of from 2 to 2J inches in length, through the skin, 

 and insert into the wound a pair of spring retractors to hold the 

 edges of the skin open. On each side of the median line of the 

 windpipe, excise with a narrow but strong scalpel a semicircular 

 piece, out of two rings of the windpipe, after having guarded the 

 resulting circle of cartilage from falling into the windpipe by 

 passing through it a sharply curved needle threaded with wire, 

 which is preferable to a material that might be liable to be cut 

 through, if accidentally touched with the knife. The circular open- 

 ing should of course be of the same diameter as the body of the 

 tube which is to be inserted. In order to interfere as little as 

 possible with the stability of the windpipe at the site of the opera- 

 tion, it is advisable to make the opening in the upper portion of 

 one cartilaginous ring and in the lower portion of the ring imme- 

 diately above it. Instead of trusting to a knife to make an opening 

 of suitable size and shape, we should employ a tracheotome (that of 

 Vandermarken for preference) with which we can cut out a circular 

 piece of cartilage of the exact size we require. This instrument 

 has an arrow-headed rod in the centre of its cutting surface, for 

 insertion into the centre of the piece of cartilage which is to be 

 removed, so as to prevent it from falling into the windpipe. Having 

 removed the piece of cartilage, the parts should be thoroughly dried 

 with a disinfected sponge (p. 70), or with a piece of antiseptic 

 cotton wool ; and the tube (which should have been previously dis- 

 infected) inserted. Performed in this manner, there will be but 

 little resulting inflammation and swelling; and the horse will be 

 ready for work in a few days. 



THE OPERATION FOR TEMPORARY TRACHEOTOMY.— 

 Here, instead of making a preliminary cut through the skin, we 

 make with one bold incision a longitudinal opening into the wind- 

 pipe ; for experience teaches us that such a proceeding is followed 

 by less bleeding and swelling of the part, than if two or more cuts 

 were made. The tube, after having been disinfected, is inserted 

 into the slit, which should have been made to correspond as nearly 

 as possible with the size of the body of the tube. In this temporary 

 operation we should of course refrain from removing any of the 

 tissue, so as to allow the wound to heal up as accurately as possible, 

 after the temporary tube has been taken out. The precaution 

 of limiting the incision to the upper portion of one ring and the 

 lower portion of the ring immediately above it, should here be 



