DIGESTION AND ABSORPTION 



305 



chemical that would be visible under the X-ray. It was found 

 that shortly after food reached the stomach a series of waves began 

 which sent the food toward the pyloric end of the stomach. If 

 the cat was feeling happy and well, these contractions continued 

 regularly, but if the cat was cross or bad tempered, the movements 

 would stop. This shows the importance of cheerfulness at meals. 

 Other experiments showed that food which was churned into a 

 soft mass was only permitted to leave the stomach when it became 

 thoroughly permeated by the gastric juice. It is the acid in 

 the partly digested food that causes the stomach valve to open and 

 allow its contents to escape little by little into the small intestine. 



The partly digested food in the small intestine almost imme- 

 diately comes in contact with fluids from two glands, the liver and 

 pancreas. We shall first consider the function of the pancreas. 



Position and Structure of the Pancreas. - The most important 

 digestive gland in the human body is the pancreas. The gland 

 is a rather diffuse structure ; its duct empties by a common opening 

 with the bile duct into the small intestine, a short distance below 

 the pylorus. In internal structure, the pancreas resembles the 

 salivary glands. 



Work done by the Pancreas. - - Starch paste added to artificial 

 pancreatic fluid and kept at blood heat is soon changed to sugar. 

 Protein, under the same conditions, is changed to a peptone. 



Appearance of milk under the microscope, showing the natural grouping of 

 the fat globules. In the circle a single group is highly magnified. 

 Milk is one form of an emulsion. (8. M. Babcock, Wis. Bui. No. 61.) 



HUNTER, CIV. BI. 20 



