136 DIGESTION 



or produces a digestive fluid by means of numerous " follicles," 

 or minute glands; this is called the intestinal juice. From 

 experiments on the lower animals, it has been ascertained that 

 this fluid exerts a solvent influence over each of the three 

 organic food principles, and in this way completes the action 

 of the fluids previously mentioned, viz. : of the saliva in 

 converting starch into sugar, of the gastric juice in digesting 

 the albuminoids, and of the pancreatic juice and bile in 

 emulsifying the fats. 



39. The Large Intestine (or Colon) is joined to the small 

 intestine at right angles to it, at some distance from its closed 

 lower end. At this point of junction there is a valve, called 

 the ileo-ccecal valve, which prevents the contents of the small 

 intestine from passing back into the latter after they have once 

 entered the large intestine. The closed lower end of the large 

 intestine (called the caecum) ends in a slender tube from two to 

 five inches in length, called the vermiform appendix, inflam- 

 mation of which produces the disease known as appendicitis. 

 From its beginning, the large intestine passes upward to the 

 under surface of the liver, this portion being called the ascend- 

 ing colon ; then it turns at right angles to the left, and across 

 the abdominal cavity just below the stomach, until it reaches 

 the left side of the abdomen, this portion being called the 

 transverse colon ; from here it passes downward, forming the 

 rectum. 



40. Absorption. With the preparation of the chyle, the 

 work of digestion is completed; but it has not yet become a 

 part of the blood, by means of which it is to reach the dif- 

 ferent parts of the body. The process by which the liquefied 

 food passes out of the alimentary canal into the blood is called 

 absorption. This is accomplished in two ways : first, by the 



38. What does the mucous membrane of the intestines secrete ? What is it called ? 

 What influence does this fluid exert ? The action of what other fluids is completed by the 

 intestinal juice ? 



39. Where is the large intestine joined to the small intestine ? Where is the ileo-csecal 

 valve ? What purpose does it serve ? What is the vermiform appendix ? What disease is 

 produced by inflammation of the vermiform appendix ? Describe the course of the large 

 intestine. 



