INTERNAL PANCREATIC SECRETION IO3 



of fat which is split up. In the intestine it is probable that 

 only a part of the neutral fats are thus split in glycerine and 

 fatty acids. The fatty acids thus formed unite with the alka- 

 line salts to form soaps, and these soaps, aided by intestinal 

 peristalsis, convert the remaining fats into an emulsion. The 

 products of fat digestion are therefore glycerine, soaps, and 

 emulsions, all of which can be absorbed in a way to be noted 

 later. While the emulsification of fats under the influence of 

 soaps (fatty acids and alkaline salts) is an undoubted effect, 

 the method of procedure is unknown. It is certain that the 

 emulsification is aided by the presence of bile, although this 

 fluid possesses no fat-splitting enzyme. 



Method of Secretion. It can be shown that the secretion 

 begins to be discharged into the duodenum very soon after 

 the entrance of food into the stomach, and continues as long 

 as intestinal digestion is in progress. Consequently the flow 

 will be intermittent if the meals are far enough apart. It is 

 almost certain that the secretion is a reflex act as a result of 

 impressions upon the mucous membrane of either the stom- 

 ach or duodenum. The acidity of the gastric juice seems to 

 be the natural stimulus and to exert its influence upon the 

 duodenal mucous membrane. This is not incompatible with 

 the early flow after the ingestion of food, for it will be seen 

 later that at least a small quantity of that food passes quickly 

 to the duodenum and carries gastric juice with it. The com- 

 position of the secretion seems to be influenced in some de- 

 gree by the character of the food. It is interesting that oils 

 increase the pancreatic flow. 



Nerve Supply. The pancreas has, besides vaso-motor 

 fibers to its vessels, distinct secretory fibers, like those of the 

 salivary glands. These fibers probably run in both the sym- 

 pathetic and the vagus. 



Internal Pancreatic Secretion. Circumstantial evidence 

 leaves scarcely any doubt that the pancreas produces some 

 substance which is discharged into the blood and markedly 

 influencees nutrition. Removal of the gland is followed by 



