8o PUNCTURE OF THE INTESTINES. 



at the most prouiinent part of the distension. After the 

 skin at this place has been cHpped or shaved and disinfected 

 grasp the trocar uith the index finger and the thumb of the 

 left hand and holding the instrument perpendicular to the 

 skin, give it a firm quick blow with the palm of the right 

 hand and drive it through the abdominal walls into the 

 intestine. With a properlj' constructed trocar of the dimen- 

 sions suggested in Figure 5 no preliminary 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 the lancet. By performing the opera- 

 tion as directed the trocar ordinarily punctures the caecum. 



Fig. 5. 



Intestine trocar with sheath. Outside diaineter 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 ingcsta entering it and these should be removed by rein- 

 serting the stilette. The intestine fir,st punctured may 

 collap.se and the flow of gas cease while the tympan3' con- 

 tinues in other parts ; this may be overcome by reintroducing 

 the stilette and pu.shing the trocar through the distal wall of 

 the bowel and into the next section of intestine bej'ond. 

 If this does not succeed the trocar may be withdrawn and 

 reinserted in a neighboring area or if need be on the opposite 

 side of the animal. In withdrawing the canula replace the 

 stilette and press the skin against the abdominal with the / 

 thumb and finger of one hand while the trocar is drawn out > 

 with the other. This tends to prevent particles of ingesta 



