470 APPLIED BIOLOGY 



392. The Small Intestine. The part of the intestine 

 connected with the stomach is smaller in diameter than the 

 extreme posterior part, and hence is called the small intestine. 

 It is very much coiled, as shown in the center of Fig. 157, 

 and is about twenty feet long. 



393. The Large Intestine is about five feet long, which 

 is one-fourth the length of the small intestine ; but the name 

 refers to the larger diameter. As shown in Fig. 157, the 

 large intestine extends upward, from the point of union with 

 the small intestine, then transversely, then downward. 

 This largest portion is often called the colon. The terminal 

 or posterior portion of the large intestine, commonly called 

 the rectum, is smaller in diameter than the colon part ; and 

 its external opening is the anus. Between the colon and the 

 rectum there is an S-shaped loop (sigmoid flexure); and 

 near the junction of the large and small intestines is the 

 vermiform appendix (or simply appendix) a tube from two 

 to four inches long and one-fourth an inch in diameter. 

 Its inflammation, due to bacteria, is appendicitis, for which 

 the usual cure is surgical removal of the organ. It has no 

 function in man ; but in the rabbit and many lower herbiv- 

 orous animals it is large and important in digestion. 



394. Liver and Pancreas. These two organs should 

 be named in the list of digestive organs, for they secrete 

 fluids which are poured into the intestine by ducts. The 

 position of the liver has been described in connection with the 

 stomach. The pancreas, which in the case of some animals 

 used as human food is called " stomach-sweetbread,"* 

 lies near the junction of the stomach and the small intestine. 

 Its main 'duct (pancreatic duct) joins the bile-duct from the 

 liver, and the fluids secreted by the two organs are poured 

 into the intestine a short distance from the stomach. 



* The neck- or throat-sweetbread sold in meat-markets is from the 

 thymus, an organ found only in young animals, such as calves and lambs, 

 and lying in the anterior part of the chest-cavity close to the neck. 



