PUNCTURE OF THE INTESTINES 77 



recumbent animal. The point of operation is in the right 

 flank about equidistant from the last rib, the extremities 

 of the transverse processes of the lumbar vertebrae an4 the 

 external angle of the ilium in the standing horse ; at the 

 uppermost point of the abdomen in the recumbent animal, 

 that is, at the most prominent part of the distension. After 

 the skin at this place has been clipped or shaved and disin- 

 fected, grasp the trocar with the index finger and the thumb 

 of the left hand and holding the instrument perpendicular 

 to the body surface, give it a firm, quick blow with the 

 palm of the right hand and drive it through the abdominal 

 wall into the intestine. 



With a properly constructed trocar of the dimensions 

 suggested in Figure 29, no preliminary skin puncture with 

 the lancet is required or advisable. The cutting end of the 

 stilette should be very long, tapering and sharp so that it 

 will cut as freely as a lancet. By performing the opera- 

 tion as directed, the trocar ordinarily punctures the caecum. 



FIG 29. 



Intestine trocar with sheath. Outside diameter of canula, 3 mm., 

 length of canula, 16 cm. 



Withdraw the stilette and permit the gas to escape 

 through the canula. The canula may become occluded by 

 particles of ingesta entering it. These should be removed 

 by reinserting the stilette. The intestine first punctured 

 may collapse and the flow of gas cease while the tympany 

 continues in other parts ; this may be overcome by reintro- 

 ducing the stilette and pushing the trocar through the dis- 

 tal wall of the bowel into the intestine beyond. If this 

 does not succeed, the trocar may be withdrawn and rein- 

 serted in a neighboring area or, if need be, on the opposite 

 side of the animal. 



