28o THE COMMON COLICS OF THE HORSE 



have doubt, however, then that doubt does not linger for 

 long ; for the passing of every hour shows a gradual 

 increase in the severity of the pains, and the oncome of 

 other and more disquieting symptoms. Foremost among 

 these is the increasing pallor of the conjunctiva and buccal 

 mucous membrane. The dread significance of this 

 symptom in incomplete twist is referred to by Walley in 

 the following words : ' In these cases, in which there is 

 only venous obstruction, the blood is constantly being 

 pressed into the veins from the arteries, and as it cannot 

 escape by its natural channels, the former become dis- 

 tended with blood to their utmost limits, and, the pressure 

 continuing, the fluid parts of the blood are finally forced 

 through the walls of the capillaries into the intestinal 

 cavity, into the peritoneum, and into the submucous and 

 subserous tissues, the denser portions of the blood and 

 the red corpuscles accumulating in the obstructed veins. 

 In many instances the walls of the capillaries give way, 

 and extravasations result. The culmination of all this is 

 death by internal hcemorrhage, the intestine acting the part 

 of a sponge, through which the life-blood of the animal is 

 gradually drained and squeezed into the peritoneal and 

 intestinal cavities, and the connective tissue of the bowel. 

 Hence the diminution in colour oi the injected membranes, 

 the failure of the pulse, and the progressive emptying of 

 the jugulars.' 



It is now, too, that tympany occurs ; when the use of 

 the trocar and cannula furnishes us with a valuable piece 

 of evidence. The evacuation of the gas gives no relief 

 from pain, and with the issuing from the cannula of the 

 last of its volume, there bubbles from the mouth of the in- 

 strument a thick, blood-tinged, light coffee-coloured dis- 

 charge—almost pus-like in appearance— the inflammatory 

 discharge from the bowel wall. This is conclusive 



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