EUMINATION. 125 



mouth. Beyond a doubt some portions of the food undergo re- 

 mastication several times. The liquid portion of the food after 

 passing through the reticulum most likely goes direct to the 

 fourth stomach. This is inferred from the dry condition of the 

 contents of the third stomach, even when the animal is in the 

 best of health, that viscus being the organ which tritiirates and 

 breaks up into small fragments, the matter which passes into it 

 thus rendering them more susceptible to the action of the gastric 

 juices of the aboraasum or stomach proper. "Where the leaves 

 in the omasum are imperfectly formed it has been observed that 

 the animal so affected will not thrive, although it may consume 

 a large amount of food. The fourth stomach, called the 

 abomasum, is the stomach proper, where the virtual act of diges- 

 tion is carried on, the contents being subjected to the action of 

 the gastric juice. Young animals existing on their mother's milk 

 employ only the fourth stomach for the digestion of the same. 

 The other stomachs, not being in use, are practically undevel- 

 oped, but as it commences to feed on other substances requiring 

 a more extensive and intricate process to extract their nutritive 

 properties the other stomachs develop in size to accommodate 

 the new conditions. By the time the food arrives in the fourth 

 stomach it has been well macerated and mixed with fluid, forming 

 a pulpy mass, ready to be submitted to the action of the pepsin 

 and acid secreted from the mucous glands of the organ. The 

 food in this viscus is converted into a mixture called chyme, 

 rendering it fit for further processes of digestion in the intestinal 

 canal. On leaving the fourth stomach the food passes through 

 a valvular orifice called the pyloric opening, the passage through 

 ■which is guarded by valves opening towards the intestines, 

 affording entrance to them, at the same time rendering a return 

 of the contents of the intestines to the stomach impossible. 



