GASEOUS INDIGESTION. 171 



like belladonna, veratrine, colchiciim, poppies, tobacco, hemlock, etc., 

 have been eaten. In such temporary abnormal states movement of the 

 rmnen is partly abolished, or at least is markedly retarded, and, as a 

 consequence of vaso-motor disturbance, the mucous membrane is pro- 

 bably not so abundantly covered with mucus nor so freely irrigated with 

 secretion, as usual. Under these conditions, if the animal, which may 

 appear perfectly well, is allowed to partake of soft, wet, fermentescible 

 food, gaseous indigestion is very likely to develop. 



Cultivated grasses, like lucern, sainfoin, clover, and especially grasses 

 grown on artificially manured fields, are regarded as particularly liable 

 to cause gaseous indigestion. This conclusion seems justified by expe- 

 rience, particularly by the fact that young shoots or young, tender 

 after-growths are very liable to fermentation. 



This exaggerated tendency to fermentation of tender grasses has even 

 been held exclusively responsible for indigestion, and the cessation of 

 peristalsis in the rumen has been considered a secondary phenomenon, 

 due to distension. 



Whether atony of the rumen be the primary condition and abnormal 

 fermentation secondary or inversely, whether fermentation be primary 

 and atony secondary, is not of importance ; for either view may be 

 adopted without altering the results, and without the theory being 

 invalidated by the objection that other animals subjected to similar 

 influences had not contracted the condition 



We have already drawn attention to the importance of the condition 

 of the animal's health for the time being. Digestive peristalsis being 

 diminished, eructation, admixture of food in the rumen, and its onward 

 movement being impeded, fermentation proceeds rapidly. As a conse- 

 quence the rumen becomes distended, and, cause and effect changing 

 places, the distension in its turn arrests peristalsis, which had previously 

 only been checked. 



Local chills, produced by ingestion of food covered with rime, hoar- 

 frost, or simply with dew, may favour gaseous indigestion ; such condi- 

 tions retard or suspend the peristaltic movements by direct local action, 

 and probably by producing vaso-motor disturbance of the mucous mem- 

 brane. In very rare cases chill has an undeniable influence, either by 

 provoking general vaso-motor disturbance, which reacts on the secretions, 

 or neuro-motor trouble. Gaseous indigestion is not uncommon in animals 

 living on dry winter food, which have been moved from their ordinary 

 quarters and sent on railway journeys or to fairs, etc. As a general 

 rule this form of indigestion is commonest in spring, when the transi- 

 tion from dry winter food to grass, etc., has not been carefully 

 effected. It is also frequent during stormy weather in full summer. 

 Marked barometric changes seem to have an influence on the general 



