DIGESTION OF THE FOOD 19 



rumen and the reticulum — which may be simply 

 regarded as store places for the food. In these 

 two compartments of the stomach the food is 

 thoroughly mixed with the saliva and any water 

 which may have been drunk, the walls of the 

 stomach assisting in the process of mixing. Some 

 time after eating, small portions of the softened 

 food are brought up again (regurgitated) into the 

 mouth, where they are masticated and salivated 

 for a second time. The return of the food to the 

 mouth is performed by the help of special muscles 

 aided by gases, such as carbon dioxide and marsh 

 gas, which arise from the food. After remastication 

 the food passes chiefly to the third stomach (omasum, 

 manyplies, or psalterium) by way of the oesophageal 

 groove. The cavity of the omasum is divided by 

 means of leaf-like extensions of the mucous mem- 

 brane provided with special muscles, giving a sieve- 

 like structure. By the slow contraction of the 

 walls of the omasum and by the rubbing together 

 of the leaf-like membranes, the food is still further 

 kneaded and ground up. When it is sufficiently 

 fine it passes to the fourth division of the ruminant 

 stomach — the abomasum or rennet, which is the 

 real digestive stomach, and resembles the simple 

 stomach of other animals. The abomasum and 

 the succeeding portion of the alimentary canal — 

 the small and large intestines — undergo peculiar 

 movements when food is in them. From the 



