GASEOUS INDIGESTION. 173 



On post-mortem examination the rumen is found to contain an 

 enormous quantity of gas, which, when collected and submitted to 

 analysis, reveals approximately the following composition : — Carbonic 

 acid, 74 per cent. ; carburetted hydrogen, 24 per cent. ; sulphuretted 

 hydrogen, 2 per cent. ; nitrogen, traces. The composition of this 

 mixture varies within certain limits, according to its origin ; but 

 carbonic acid always predominates. 



Lungwitz, after elaborate experiments with different foods kept in 

 closed vessels at the body temperature and with similar agents fed for 

 days as an exclusive aliment to oxen provided with a fistula of the rumen 

 for purposes of collection, found carbonic dioxide the predominating gas 

 in all cases, though the proportion varied with the nature of the food. 



Marsh gas varied from 16 to 39 per cent., being especially abundant 

 in cases of abstinence. Hydrogen sulphide was found only in traces. 

 Oxygen and nitrogen were present in small amount, and were attributed 

 to air swallowed with the food. In fermentation the oxygen may be 

 completely consumed. 



The abdominal organs, particularly the intestine, are congested, as a 

 result of impediment to the venous circulation. The thoracic organs 

 exhibit the lesions of asphyxia. 



Pathogeny. Death is due to carbonic acid poisoning, brought about 

 in two different ways — viz., progressive asphyxia, caused by inability to 

 inflate the lungs, and absorption of carbonic acid gas from the rumen ; 

 by virtue of the laws of diffusion, part of the gas contained in the rumen 

 passes into the blood. 



The diagnosis is always very easy, and even farm servants may 

 recognise the condition. 



The prognosis varies, according to the rapidity with which the 

 disease develops. In rapid cases, where the condition is fully estab- 

 lished in thirty minutes to one hour, asphyxia may be threatened 

 from the beginning; but in others, e.g., when the attack follows con- 

 sumption of dry food, tympanites may develop slowly, only attaining 

 its maximum intensity after a considerable lapse of time. In general 

 one may say that tympanites is grave in proportion to the rapidity 

 with which the gas is generated. 



Treatment. From the prophylactic point of view, it is necessary to 

 avoid suddenly changing animals from dry to green food ; the transition 

 should be effected by giving mixtures of dry and green food. 



Curative treatment comprises a large number of methods. 



The latest, and one of the most practical, consists in massage of 



the left flank. The open hand is applied to the left flank and sharj)ly 



pressed directly downwards, care being taken not to injure the parts. 



This manipulation excites reflex action, awakens the dormant contractility 



