DIGESTION AND ABSORPTION. 



Ill 



traction of successive rings of muscular fibers, through 



the gullet into the stomach. There it 



remains for a time. It has not been 



long in the stomach before portions of 



it are digested, and these begin to pass 



through its walls. Other portions are 



not digested by the gastric juice. But 



the whole is reduced to a fluid-like 



gruel, and then passes the pylorus 



into the small intestine. In this state 



it is called chyme. Here it meets the 



bile and the pancreatic juice. These 



mix with the fat, and make an emul- 

 sion which is called chyle. The rest 



of the food is also*changing, and being 



dissolved out of the branny and fibrous 



parts which can not be digested. 



4, In the lining of the small intestine, we find a special 



apparatus for absorption; and it is here that absorption 



goes on most actively. 



This lining has a soft look, 

 like velvet. With a micro- 

 scope we can see that the 

 reason that it looks so, is, that 

 it actually has a nap, like 

 velvet. This nap is made of 

 innumerable short, thread- 

 like projections, which are 

 called villi (Latin, villus, a 

 tuft of hair). 



5, Each villus contains a 



net-work of fine blood-vessels, and, also, one of another 



Fig. 43. 



VILLI or THE SMALL IN- 

 TESTINE MAGNIFIED. 



Fig. 44. 

 SHOWING THE VESSELS IN VILLI. 



