GASTRIC DIGESTION. 61 



parative immunity of the fourth stomach from disease, 

 while the first three, like the stomach of the horse, are 

 very obnoxious to disorder. The possibility of incredibly 

 long fasts on the part of the ruminant, may be explained 

 by the constant presence of a large mass of food in the 

 paunch, for although rumination may be almost or quite 

 suspended, yet if water is freely taken, small quantities are 

 continually transferred from the first two stomachs to the 

 third and fourth/' 



GASTRIC DIGESTION". As before mentioned, it is in the 

 fourth stomach that true digestion begins. The innumera- 

 ble glands of the stomach secrete the gastric juice, and 

 when food comes into this stomach the juice is poured out 

 in large quantity. It has a sour taste and smell. It con- 

 tains muriatic acid and a little pepsin. The latter acts 

 strongly upon the albuminoids contained in the food. It 

 makes them soluble in water, and thus in condition to 

 enter into the circulation. The quantity of pepsin is very 

 small, but appears to have the power of acting over and 

 over many times in connection with the muriatic acid in 

 rendering the albuminoid matter soluble. The soluble 

 carbo-hydrates (as we have seen converted into sugar by the 

 saliva) are absorbed by the blood-vessels of the stomach 

 and enter into the circulation, and the soluble albuminoids 

 or protein is absorbed by the lymphatic vessels of the 

 stomach. But there is much of the nutriment in the food 

 not liberated in the stomach, and all this passes through 

 the pylorus into the intestines (at G, fig. 3). Let us ex- 

 amine cursorily : 



INTESTINAL DIGESTION. The alimentary canal is con- 

 tinued from the stomach, in the abdominal cavity, by a 

 long tube doubled on itself in many folds, and ends at the 

 posterior opening of the digestive apparatus. This long 

 tube is the intestine. It is narrow and uniform in size in 



