CONDITIONS OF THE PANCREATIC ENZYMES 383 



triatomic alcohol, and three fatty-acid radicles which may or may not be 

 identical, when an alkali (potassium hydrate) is added to it two changes 

 take place; first, the oil or fat is split up into glycerin and its fatty acid; second, 

 the fatty acids combine with the alkali to form soaps which are chemically 

 known as stearate, oleate, or palmitate of potassium according to the particular 

 fatty acid or acids involved. Saponification thus means a chemical splitting 

 up of oils or fats into new compounds, and emulsification means merely a 

 mechanical splitting up into minute particles. The pancreatic juice has 

 been for many years credited with the possession of a special ferment, 

 which was called by Claude Bernard steapsin, and which is a lipase or 

 fat-splitting ferment. This ferment has not been isolated, but its pres- 

 ence may be demonstrated by adding portions of the fresh pancreas 

 to butter or other fat and maintaining the proper temperature. Its 

 action is made manifest by the liberation of butyric acid, which imparts the 

 typical odor to rancid butter. 



The older theory was that only a small portion of the fat eaten was thus 

 changed into soap, and that the function of the saponified fat was to assist 

 in the emulsification of the remaining major part, a process favorably 

 influenced by the bile. Although the proper emulsification of fat is indeed 

 a preliminary step favoring more effective contact of the fat splitting enzyme, 

 lipase, we now know that all the fat is dissociated into fatty acid and glycerin 

 before abosrption can occur. When in disease the entrance of the pancreatic 

 juice and the bile into the intestine is interfered with, the feces contain an 

 excess of fat. 



All recent experiments, however, tend to support the view of Pflliger 

 that the entire fat of the food is changed into fatty acids and glycerin; that 

 the fatty acids are entirely, or in part, changed to soaps; and that these soaps, 

 or mixture of soaps and free fatty acids, are absorbed in solution. The 

 chief facts favoring this view are that: (i) The reaction of lipase is sufficiently 

 rapid to allow the saponification of a full fatty meal within the ordinary 

 period of digestion; (2) histological examination has never shown that fat 

 particles can pass into a columnar cell, and droplets have not been found in the 

 broad striated border of the cell; (3) the fat globules found in columnar cells 

 after a fatty meal grow steadily larger as the period of absorption progresses, 

 indicating that they are deposited from solution; (4) the fatty acids are easily 

 soluble in bile solutions, and the solubility of the soaps is greatly increased 

 by the presence of bile. The fat constituents, according to this theory, are 

 recombined in the columnar cells to form neutral fats where their presence 

 can be easily demonstrated by methods of staining. 



Conditions which Influence the Action of the Pancreatic Enzymes. 

 The various pancreatic enzymes are influenced by heat, by the presence of 

 an excess of digestion products, etc., in the same way as ptyalin and pepsin. 

 Pancreatic enzymes act in a neutral, but best in an alkaline solution. The 



