DISEASES OF THE DIGESTIVE SYSTEM 



29 



of three or four gallons. The left portion is lined with a cnticuhtr 

 mucous membrane, and the right portion with a glandular 

 mucous membrane that has in it the glands that secrete the 

 gastric juice. The most important digestive change in the feed 

 is the action of the gastric juice on the proteids and their conver- 

 sion into the simpler products, proteoses and peptones. 



Ruminants have a compound stomach (Figs. 9 and 10). 

 The capacity of the stomach of the ox is between twenty and 

 thirty gallons. The four compartments into which it is divided 



Fig. 10. — AvSection of the wall of the rumen and reticulum, showing the oesophageal groove: 

 (C, C) lips of groove; (B) opening from cesophagus; and (A) opening into omasum. 



are the rumen, reticulum, omasum, and abomasum or true stom- 

 ach. The rumen is the largest compartment, with a capacity of 

 more than twenty gallons. The reticulum is the smallest, with 

 a capacity of about one-half gallon. 



After a brief mastication, the food passes directly to the 

 rumen. Here it is subjected to a churning movement that mixes 

 and presses the contents of the rumen forward in the direction 

 of the oesophageal opening, where it is ready for regurgitation. 

 It is then carried back to the mouth, remasticated and returned 



