PUNCTURE OF THE INTESTINES. loi 



we reach in the horse the point of operation on the left and 

 right sides respectively. Clip or shave the designated inter- 

 costal area immediately above the thoracic vein. Grasp the 

 trocar firmly with the thumb and index finger of one hand 

 at such a distance from the point as will permit the canula 

 to enter the chest. After the skin over the seat of operation 

 has been drawn aside by the hand, place the trocar at the 

 anterior border of the rib with the point inclined slightly 

 forward and with a sharp blow with the palm of the other 

 hand drive the instrument through the skin, cutaneous and 

 intercostal muscles, internal thoracic fascia and pleura into 

 the pleural sac. When the resistance ceases, the thoracic 

 cavity has been entered. Remove the stilette and permit 

 the pus, lymph, or other fluid to escape. This flow is at first 

 continuous, but later becomes rythmic, synchronous with 

 respiration. The intermission of the flow during inspiration 

 permits air to enter the pleural cavity unless precautions 

 are taken against it ; this is most readily obviated by slipping 

 one end of the rubber tubing over the exposed part of the 

 canula and placing the other extremity in the receptacle for 

 the fluid where it will be submerged. This will not only 

 prevent aspiration of air into the chest but will act as a 

 siphon to aid in the withdrawal of the fluid from the pleu- 

 ral cavity. In the absence of the tubing the entrance of 

 air may be avoided by closing the canula with the finger 

 after each expiration. 



20. PUNCTURE OF THE INTESTINES. 



Figs. 7-8. 



Object. The relief of intestinal tympany. 



Instruments. Razor, scissors, trocar. 



Technic. Puncture of the intestine is preferably per- 

 formed on the standing horse but may be carried out on the 

 recumbent animal. The point of operation is in the right 



