Diseases of the Stomach. 439 



(gastric atony), the churning and mixing of the gastric contents 

 with the secretion are not thoroughly accompUshed. When the 

 ingested matter is thus inefficiently dealt with the undigested 

 material is apt as a result to remain stagnant in the viscus, and 

 this in turn favors increased fermentation and putrefaction. As 

 gases are very likely to be present among the products of these 

 processes, flatulence of the stomach {meteorisin, from nereupi^eiv, 

 to inflate) may be expected, varying in its intensity ac- 

 cording as to whether the gas finds its way through the pylorus, 

 is absorbed or finds an outlet through the gullet in belching, or 

 whether it fails to escape. 



Delay in emptying of the stomach or retention of the contents 

 favors gastric dilatation. A distended stomach because of its 

 increased volume causes pressure influtnces upon the adjacent 

 parts, compresses the liver, vena cava, etc., interferes with the 

 diaphragmatic movements and thus renders respiration difficult. 

 Even in moderate degrees of distension the absorptive powers 

 of the gastric mucous membrane is dinnnished because of the 

 tension of the lymphatics and blood vessels. The distended wall 

 of the stomach may rupture and fatal haemorrhage from the torn 

 blood vessels quickly terminate life. Digestive faults in the first 

 stomach of ruminants occur in the same general way as above, 

 but with the difference that there is here no secretion from the 

 gastric mucous membrane and we have to consider merely the 

 macerating properties of the fluid swallowed, mixed with saliva. 

 In these animals accumulation of gas and tremendous distension 

 invariably occur, either suddenly or gradually, when the con- 

 tractile power of the wall of the paunch is lost. This may be 

 caused by a number of influences, as chilling" of the mucous sur- 

 face of the paunch by frozen or rain-drenched food, overfeeding 

 or overwork without allowance of time for rumination, or toxic 

 substances capable of causing paresis of the gastric wall and met 

 in various food stufifs. as lucerne or clover. ^leteorism may also 

 be noticed when belching of gas is prevented by constrictions of 

 the oesophagus. 



Exaggerated gastric mbvemcnts occur especially in connection 

 with pyloric obstruction, or from the influences of chemical ma- 

 terials which directly irritate the mucous membrane of the viscus 

 or the smooth muscle of its walls, or mav be caused indirectlv 

 by influences acting on the medulla oblongata (reflexly and by 

 irritation of the vagus). The violent contractions of the muscle 



