144 THE ABDOMEN. 



three ferments, amylopsin for the digestion of starch, 

 trypsin for the digestion of proteins, and steapsin for tho 

 digestion of fats. By it, as by the saliva, starch is turned 

 into sugar or maltose, in which form it is absorbed, while 

 proteins are converted into peptones, as they are in the 

 stomach. Since, however, fats are acted on nowhere else, 

 the chief function of the pancreatic juice may be con- 

 sidered to be the digestion of fats. Having broken 

 through their albuminous envelope, it divides them into 

 glycerine and fatty acids and then emulsifies them with 

 the assistance of the bile. 



The food also comes in contact with the succus enteri- 

 cus, a juice secreted by the glands of Lieberkiihn in the 

 small intestine, whose chief action is the conversion of 

 sugar into glucose. 



Absorption. As the food is absorbed from the intes- 

 tine it is liquid and entirely digested and is known as 

 chyle. Practically all absorption takes place from the 

 small intestine, though there is a little in the large in- 

 testine. It takes place in two ways: 1. through the por- 

 tal vessels and 2. through the lacteals, which are the 

 lymphatic vessels of the small intestine. Fats are ab- 

 sorbed practically entirely by the lacteals. They enter 

 the cells covering the villi, travel thence to the lymph 

 spaces, and so into the lacteal or main lymph channel, 

 whence they are carried to the thoracic duct and the 

 general circulation. From the blood they are absorbed 

 as fat and stored up as adipose or fatty tissue, which is 

 found throughout the body in connective tissue about 

 the organs. Organic salts and water are for the most 

 part absorbed by the portal system, which they reach 

 through the capillaries of the villi and through which 

 they go to the liver. Starches, in the form of sugar, 

 pass between the cells of the villi into the lymph spaces, 

 from which they are taken up by the capillaries. On the 

 way to the liver maltose becomes dextrose. Proteins, 

 in the form of peptones, pass through the layer of 

 epithelial cells to the lymph spaces and then to the 



