TRYPSIN 363 



Amylopsin. Starch is converted by amylopsin into maltose by hydro- 

 lytic action similar to that of ptyalin, erythro-dextrin and one or more 

 achroo-dextrins being the intermediate products. The amylolytic enzyme 

 of the pancreatic juice, which cannot b2 distinguished from ptyalin, is called 

 amylopsin. The maltose thus formed is converted to dextrose by the maltase, 

 in which form it is ultimately absorbed. 



Pancreatic juice, according to certain observers, possesses the property 

 of curdling milk. It contains a special ferment, rennin, for that purpose. 

 The ferment is distinct from trypsin, and will act in the presence of an acid 

 (W. Roberts). The milk-curdling ferment of the pancreas is, in some pan- 

 creatic extracts, said to be quite powerful, insomuch that i c.c. of a brine ex- 

 tract will coagulate 50 c.c. of milk in a minute or two. 



Steapsin orLipase. Oils and fats are emulsified and saponified by the pan- 

 creatic secretion. The terms emulsification and saponification may need a 

 little explanation. The former is used to signify an important mechanical 

 change in oils or fats, whereby they are made into an emulsion or, in other 

 words, are minutely subdivided into small particles. If a small drop of an 

 emulsion be looked at under the microscope it will be seen to be made up of 

 an immense number of minute rounded particles of oil or fat of varying 

 sizes. The more complete the emulsion the smaller are these particles. An 

 emulsion is formed at once if oil or fat, which when old is slightly acid from 

 the presence of free fatty acid, is mixed with an alkaline solution. Saponifi 

 cation signifies a distinct chemical change in the composition of oils and fats. 

 An oil or fat being made up chemically of glycerin, a triatomic alcohol, and 

 one or more fatty-acid radicles, when an alkali (potassium hydrate) is added 

 to it and heat is applied, two changes take place: first, the oil or fat is split up 

 into glycerin and its corresponding fatty acid; second, the fatty acid combines 

 with the alkali to form a soap which is chemically known as stearate, oleate, 

 or palmitate of potassium. 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 smells 

 like rancid butter. 



The generally accepted theory is that only a small portion of the fat which 

 is eaten is thus changed into soap, and that the function of the saponified fat 

 is to assist in the emulsification of the major part, a process which is favorably 

 influenced by the bile. The proper emulsification of fat is a necessary pre- 

 liminary to its absorption, for when in disease the entrance of the pancreatic 



