76 PUNCTURE OF THE CHEST 



one reaches in the horse the 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 instrument through the skin, cutane- 

 ous 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 pleural cavity. In the absence of the tubing the 

 entrance of air may be avoided by closing the canula with 

 the finger after each expiration. 



30. PTTNCTUBE OF THE INTESTINES 

 Figs. 28, 29 



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 



