IMPACTION OF THE RUMEN. 175 



None of these methods of treatment, therefore, should be used 

 exclusively, but all may be utilised as auxiliaries to mechanical or 

 surgical measures, and all should be preceded by the use of the pro- 

 bang and puncture of the rumen. 



The first of these operations, the technique of which scarcely requires 

 description, is often of little value ; for the solids and liquid contents of 

 the rumen being permeated with gases, rise as a fermenting mass into 

 the upper portions of the rumen, and continually obstruct the open end 

 of the catheter, so that very little gas escapes. 



Puncture of the rumen is much more effective and easier to perform. 

 The owner himself often operates with an ordinary pocket knife, some- 

 times introducing a couple of fingers or a short length of elder- wood 

 tube into the wound thus produced. 



The incision should be made at one stroke, for any hesitation may 

 cause the wall of the abdomen to recede from the rumen, which lies 

 immediately below. Should gas escape under the skin, emphysema, 

 which often extends to the loins and along the quarters, may be i^ro- 

 duced, and may be followed by diffuse subcutaneous suppuration, re- 

 sulting from pyogenic germs entering the subcutaneous tissue. 



Large quantities of gas escape from the puncture, sometimes with 

 such force as to drive out the canula. The flow of gas then ceases. In 

 other cases the tube becomes blocked ; because, as the pressure within 

 the rumen diminishes, the gases dissolved or mixed with the partially 

 digested food are freed, and the whole contents of the rumen become 

 converted into an aerated, bubbling mass. Liquid or semi-liquid materials 

 may be ejected to some distance, or may pass between the skin and the 

 muscles, or between the walls of the rumen and the abdomen, producing 

 various complications, like necrosis, abscess formation, etc. Such acci- 

 dents can be avoided by exercising firm pressure with the fingers on the 

 tissues surrounding the canula. 



Even when the rumen has resumed its normal size recovery is not 

 certain, and may not occur for several hours, or even several days, after- 

 wards. The patients should therefore be kept under observation for 

 some time, and it is usually best to leave the canula in place for one or 

 two daj^s, and to put the animal on low diet. 



Necrosis of aponeurotic tissues, fistula formation, and local peri- 

 tonitis only occur if the instrument is dirty or is introduced in a 

 wrong direction. 



IMPACTION OF THE RUMEN. INDIGESTION AS A RESULT OF OVER-EATING. 



In this condition the rumen is over- distended with food. The 

 symptoms are principally due to abnormal fermentation, the peristaltic 



