PUNCTURE OF THE INTESTINES. 79 



thiimb and index finger of one hand at a distance from the 

 point which will permit the canula to enter the chest. Af- 

 ter 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, skin muscle, intercostal muscles, internal 

 thoracic fascia and pleura into the pleural sac. When the 

 resistance ceases, the thoracic cavity has been entered. Re- 

 move the stilette and permit the pus, lymph, or other fluid 

 to escape. This e.scape is at first continuous, but later be- 

 comes rythmic, synchronous with respiration. The inter- 

 mission of the outflow during inspiration permits air to enter 

 the pleural cavity unless precautions are taken against it ; 

 this is most readily obviated by slippin.g one end of the rub- 

 ber tubing over the exposed end 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 syphon to aid in the aspi- 

 ration of the fluid from the pleural cavity. In the ab.sence 

 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. 4, 5. 



Object. The relief of intestinal tympany. 



Instruments. Razor, scis.sors, trocar, disinfectants. 



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 

 flank about equi-di.stant from the last rib, the extremities of 

 the transverse processes of the lumbar vertebrae and the ex- 

 ternal angle of the ilium in the standing horse, at the upper- 

 most point of the abdomen in the recumbent animal, that is, 



