DIGEXTIOX AND AliSORPTION. 



107 



Fig. 41. 

 STOMACH GLANDS op A L'i. 



stands at the mouth of each one. This overflows, and 

 another follows; and so it keeps coming, until there is 

 just enough to mix with the food taken. Then it stops. 

 Meantime the muscular walls have been turning and 

 squeezing the food, some- 

 what as the teeth and 

 tongue do in the mouth. 



30. The outlet of the 

 stomach is at its right 

 end, and is guarded by 

 the pylorus (from a Greek 

 word, meaning keeper of 

 the gate). This pylorus 

 is a ring of muscular 

 fibers, which surrounds 

 the canal, and, by con- 

 tracting, closes it. Its duty 



is, to let no food pass out until it has been properly acted 

 on by the stomach. When the food is hard and indigest- 

 ible, the laboring stomach often becomes exhausted and 

 distressed. It would fain get rid of its contents : but the 

 pylorus steadfastly resists, until vomiting occurs; or else, 

 this resistance being overcome, the troublesome matters 

 pass down, to cause similar discomfort in the intestines. 



31. Near the beginning of the small intestine, two little 

 tubes open into it by the same orifice. If we follow these 

 back a short distance, one will lead us to the liver, the 

 other to the pancreas. 



THE LIVER. 



32. The liver is a large organ situated at the lower 

 border of the ribs, on the right side. It is a gland, and it 

 does three things: 



