POOD AND DIGESTION 63 



be extracted from the mucous membrane of the intes- 

 tines which act 011 various foods, breaking the products 

 of gastric and intestinal digestion into simpler bodies, 

 better fitted either for absorption or to be employed as 

 tissue builders. The action of enterokinase, erepsin and 

 secretin have been alluded to. 



Fig. 15. Injected lacteal vessels in two villi of human intestine. (Teich- 

 mann.) X 100. I,acteals filled with white substance and blood vessels 

 with dark. 



Bile is not a digestive fluid, but it so largely promotes 

 the splitting and absorption of fats that its presence as 

 an auxiliary is essential to health. 



Absorption in Small Intestines 



Absorption of Proteins. The greater part of digested 

 proteins is absorbed by the blood vessels of the intes- 



