866 THE EXTERIOR OF THE HORSE. 



Besides, to suppose that it is produced by an eructation would make it 

 necessary to admit that horses which crib have the power of ejecting 

 into the oesophagus tlie gas contained in their stomach. Such is not 

 the case ; for we have never seen, at the autopsy, any abnormal dila- 

 tation of the cardiac end of the stomach ; a stomach inflated through 

 the pylorus will not allow any escape of air from the oesophagus, free 

 from ligature, no matter what pressure may be employed. 



We will add that if the guttural air were an eructation, as is be- 

 lieved, we could not understand why such horses suffer from abdominal 

 tympanites still more when they crib persistently, Avhilst we know 

 that tlieir meteorism disappears promptly as soon as the gas is ejected 

 through the anus, H, Bouley affirms, however, that he saw a horse 

 belch and perceived the grassy odor of the gases ejected by the animal. 

 An observation of the same kind has been made by one of our pupils, 

 which case we published in the Journal de P^cole veterinaire de Lyon. 

 By no means disputing the exactness of these facts, we simply consider 

 them to be pure coincidences, very rare and altogether exceptional. 



What we maintain is that horses which crib swallow air. 



To demonstrate this, it suffices to expose the oesophagus and slightly 

 raise it, as in performing oesophagotomy. We shall then see, after each 

 effort, a mouthful of air descending through this passage in the direction 

 of the stomach. 



Another and even more palpable proof consists in collecting, imme- 

 diately after death, the gases contained in the stomach and the first 

 portions of the intestine, and submitting them to a chemical analysis. 

 Clement, at our request, undertook these researches, when he was prin- 

 cipal of the chemical laboratory in the veterinary school of Alfort. In 

 the stomach, always more or less distended, he found pnre air ; in the 

 small intestine he also found air, but it was modified on account of its 

 mixture with the gaseous products of digestion. 



These experiments, therefore, show that the essential character of 

 this vice is a deglutition of air, frequently laborious and at such times 

 accompanied by a noise resulting from an effort having its seat in the 

 larynx. 



The horse does not always perform this air-swallowing in the same 

 manner. Sometimes he does not take any point of support ; sometimes, 

 on the contrary, the inferior extremity of his head is supported upon a 

 resisting body in order to render the act easier. From these different 

 methods come the distinctions of cribbing in the air, or wind-sucking, 

 and cribbing with support, according to the method employed by the 

 animal. 



