PUNCTURE OF THE INTESTINE. 689 



of making the puncture when the animal is lying down, and care- 

 fully guard against the chance of injury to the horse, while the 

 puncture is being made, from his throwing himself about when 

 suddenly seized with colicky pains. The animal can be kept lying 

 down by means of hobbles. 



The operation itself is a very simple affair. The operator, having 

 placed himself on the right side of the horse, should make an 

 incision through the skin with the knife, at the point chosen, of a 

 little less than half an inch in length, in order to allow the trocar 

 to penetrate easily, and prevent air getting into the loose tissue 

 underneath the skin. Then, while holding the instrument with 

 his left hand, he should place its point into the incision, at right 

 angles^ to the surface of the skin, and strike the handle a sharp 

 blow with the palm of the right hand, so as to make the point of 

 the trocar penetrate the intestine. The gas escapes with violence 

 on the trocar being withdrawn out of the cannula. In proportion 

 as the gas escapes, so does the inflation of the intestines diminish. 

 Take care to press the cannula as far as it will go, so that its 

 lower end may be in the intestine, and not remain between it and 

 the flank. If the escape of gas stops suddenly, on account of the 

 cannula becoming obstructed, the instrument should be mopped 

 out by means of a small metallic stem prepared for that purpose, 

 but not with the trocar, which might wound the intestine. If 

 these means do not succeed, a second puncture some distance from 

 the first one, may be made. 



The cannula should be kept in until the gas ceases to escape and 

 the inflation has nearly disappeared. It is always prudent not to 

 leave the instrument longer in than a quarter of an hour, so as to 

 avoid the chance of peritonitis in some measure at least. Some 

 practitioners take it out after five or six minutes, if the escape of 

 gas has ceased by that time. Another objection against allowing 

 the canimla to remain long in, is that it might wound the intestine 

 during the struggles of the animal, or on the collapsing of the 

 bowel. 



To remove the cannula, seize it with the right hand, and raise 

 it rapidly, but without roughness. 



There is no need to do anything to the external wound ; as the 

 puncture becomes closed up by reason of the hole made through 

 the skin, shifting its position away from that made through the 

 abdominal muscles, on the swelling going down. 



The practice of injecting medicines through the cannula is 

 dangerous; for the fluid might go the wrong way and escape into 

 the abdominal cavity, with the very probable result of peritonitis 

 and death. It is much better, as a rule, to give a drench in the 

 ordinary manner. 



44 



