DIGESTION, CIRCULATION, AND ABSORPTION 277 



curdles milk. Soup for the first course of a 



dinner starts the flow of and temporarily satis- 

 fies the craving for food. This tends to prevent 



c. In the small intestine. (Nearly all digestion carried on here.) 



( 1 ) Pancreatic juice acts on 



(2) Bile aids in absorption of 



(3) Intestinal juice acts on 



d. Large intestine. 



(1) Practically no digestion. 



e. Fill in the following summary : 



PROBLEM XLVII 



A study of where and how digested foods pass into the 

 blood (absorption). 



Materials. Tripe, and charts showing the plan of absorption 

 and the villi of the human intestine. 



Note. Observe how the mucous membrane of the small in- 

 testine is thrown into ridges and small elevations (villi). 



a. The Villi 



Observations. Note the microscopic blood vessels (capil- 

 laries) entering a villus. If the liquid food is on the outside 

 of the villus, how might it get inside the blood vessels ? 



Note. The small blood vessels beginning here finally unite, 

 and carry proteid, water, salts, and sugar to the liver. 



