24 THE ECONOMICS OF FEEDING HOESES 



with saliva, which begins the process of digestion by 

 attacking the starches and converting them into sugar, 

 which can be absorbed. This action of the saliva con- 

 tinues for some time after the food has reached the 

 stomach, but gradually the stomach wall pours out the 

 active digestive gastric juice. This attacks especially 

 the proteins, breaking down their complex molecules into 

 the smaller and simpler peptones, which can be absorbed 

 through the intestinal wall and taken up into the blood- 

 stream. After a variable time — three to four hours — 

 the food-mass, now in the form of a semi-liquid paste, 

 is passed on from the stomach into the small intestine, 

 and here it comes in contact with the bile and pancreatic 

 juice. These digestive secretions further break down the 

 compounds presented to them, the bile especially attack- 

 ing the fats and causing them to assume the form of 

 minute droplets, and the pancreatic juice acting on any 

 starches not yet converted into sugar, on any proteins 

 not yet changed into peptones, and on the fat droplets, 

 to form a soluble compound which can be absorbed. 

 Now, the intestinal wall has ramifying in it very numer- 

 ous fine capillary blood vessels and lymphatics, and when 

 the digestive juices have acted on the food in the 

 manner described, the newly formed sugars, peptones, 

 and soluble fatty compounds (soaps) are in close contact 

 with the blood and lymph in these vessels, so that it is 

 easy for them to pass through, get into the blood, and 

 become available for the food needs of the animal. This is 

 the process of absorption, which is especially active through- 

 out the small intestine and, to a less degree, in the large 

 bowel. The unabsorbed part of the food is propelled 

 along the small intestine by its muscular wall and 

 reaches the large intestine. Here the chief digestive 



