816 
GUIDES IN PUNCTURING THE BOWEL. 
fermentive changes and production of gas still continue, even under 
considerable pressure. 
Internal medicaments, supposed to neutralise or absorb intestinal 
gases, act too slowly, and, like those given to prevent fermentation, enter 
the colon too late to be of benefit. As the natural passages for discharge 
a, Femoral artery ; b, posterior rena casa ; c and c', loops of small intestine ; cl, rectum ; 
e, colic artery; /, inferior colic artery ; g, superior colic artery ; h, arteries of the rectum • 
i, ureter. (After Ellenberger and Baum.) 
of gas may be filled with solid matter, the only method of staving off 
suffocation often resolves itself into removal of gas by trochar. 
The operation acts like puncture of the rumen ; but puncture of the 
bowel in the horse is more dangerous, even though recent cases, like 
Friedberger’s, show that risk of peritonitis is greatly diminished by 
careful antisepsis. The precise cause of the greater vulnerability of the 
peritoneum in horses is still unknown, though it is clear that peritonitis 
