PUNCTURE OF THE INTESTINES. 87 



point of operation on the left and right sides respectively. 

 Clip or shave the designated intercostal 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 in- 

 strument through the skin, cutaneous and intercostal mus- 

 cles, 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 can- 

 ula and placing the other extremity in the receptacle for 

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

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

 syphon 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. 



21. puncture op the intestine'^. 

 Figs. 4, 5. 



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 



