26 The Digestive Process. 



and rectum minister but little to that process. 

 The capacity of the large intestines greatly ex- 

 ceeds that of the small. The caecum will contain 

 about four gallons of fluid, the colon about 

 twelve, and the rectum about three gallons. 



THE DIGESTIVE PROCESS. 



The process of digestion is most complex and 

 important, and deservedly receives an extended 

 notice in all authentic works on animal physi- 

 ology. It is impossible here to do more than 

 briefly notice the leading stages, which are in- 

 dispensable, but sufficient towards explaining 

 generally the object for which these pages are 

 written. 



Gastric digestion. In the stomach the food, 

 already incorporated with the salivary and other 

 secretions, is subjected to peculiar movements or 

 contractions of the muscular walls, described 

 usually as a " churning action/' It is thus 

 moved from one part to another and further in- 

 corporated with secretions (gastric juice) derived 

 from glands (gastric glands) situate in the walls 

 of the organ. 



The gastric juice possesses acid properties, and 

 a peculiar principle termed pepsine, which with 

 the action of the stomach effects a reduction of 

 the food to a uniform mass. The particles are 

 in a fine state of division, and albuminous prm- 



