I QO PHYSIOLOGICAL CHEMISTRY 



tein does not swell as is the case in gastric digestion, but becomes more 

 or less "honey-combed' ' and finally disintegrates. 



The presence of active pepsin in the contents of the intestine has 

 been demonstrated by Abderhalden and Meyer. 1 It may possibly be 

 that pepsin may play a part in the profound intestinal proteolysis which 

 has up to this time been assigned to trypsin and erepsin (see chapter on 

 Gastric Digestion). 



The pancreatic juice which is collected by means of a fistula pos- 

 sesses practically no power to digest protein matter. A body called 

 enterokinase occurs in the intestinal juice and has the power of converting 

 trypsinogen into trypsin. This process is known as the "activation" of 

 trypsinogen and through it a juice which is incapable of digesting pro- 

 tein may be made active. (For further discussion of enterokinase 

 see chapter on Intestinal Digestion.) Mendel and Rettger 2 and others 

 have demonstrated that activation of trypsinogen into trypsin may be 

 brought about in the gland as well as in the intestine of the living 

 organism. The manner of the activation in the gland and the nature 

 of the body causing it are unknown at present. Prym 3 denies that 

 such an activation occurs. After the death of the animal at least 

 part of the trypsinogen in the pancreas is changed to trypsin as shown 

 by the fact that the extract of the gland is active. 



Delezenne claims that trypsinogen may be activated by soluble 

 calcium salts. He reports experiments which indicate that proteolytic- 

 ally inactive pancreatic juice, obtained directly from the duct, when 

 treated with salts of this character, assumes the property of digesting 

 protein material. This process by which the trypsinogen is activated 

 through the instrumentality of calcium salts is very rapid and is desig- 

 nated by Delezenne as an "explosion." The suggestion of Mays that 

 there may possibly be several precursors of trypsin one of which is 

 activated by enterokinase and the others by other agents, is of interest 

 in this connection. 



Boldyreff 4 has demonstrated the presence of trypsin in the stomach 

 due to the regurgitation of duodenal contents through the pylorus 

 (see Chapters VII and VIII). Others 5 have confirmed this finding (see 

 chapter on Gastric Analysis). 



Pancreatic amylase (amylopsin), the second of the pancreatic en- 

 zymes, is an amylolytic enzyme which possesses somewhat greater diges- 

 tive power than the salivary amylase (ptyalin) of the saliva. As its 



Abderhalden and Meyer: Zeit. physiol. Chem., 74, 67, 1911. 

 2 Mendel and Rettger: American Journal of Physiology, 7. 

 3 Prym: Pfliiger's Archiv, 104 and 107. 



4 Boldyreff: Transactions of the nth Pirogoffs Congress of Physicians, St. Petersburg, 

 1910. 



6 Spencer, Meyer, Rehfuss and Hawk: American Jour. Physiol., 39, 459, 1916. 



