ENTEROKINASE 41 



Mention should be made also of the fact that acid exhibi- 

 tion is capable of stimulating reflexly the pancreatic secre- 

 tion not only from the duodenum but also, as discovered by 

 Popielski, 13 and by London and C. Schwarz, 14 from a large 

 part of the small intestine. London and Schwarz determined 

 the fact that besides the duodenum, the whole of the jejunum 

 and the upper portion of the ileum, but not the middle part of 

 the ileum, manifest this ability, which therefore resides in 

 about two-thirds of the entire length of the intestine. 



Besides secretin and cholin, pilocarpin is capable of 

 stimulating the secretory activity of the pancreas if intro- 

 duced into the blood; albumoses and other similar sub- 

 stances may act in the same way. 15 



Enterokinase. Passing to consideration of the pancre- 

 atic secretion itself, Pawlow is to be credited with the impor- 

 tant discovery that trypsin is not secreted in a completed 

 form. The secretion as it passes out of the duct of the gland 

 contains rather a trypsin-zymogen, which is activated by con- 

 tact with an agent arising from the intestinal mucosa, enter o- 

 kinase, and is transformed thereby into true trypsin. This 

 puzzling agent, which is also doubtless of importance in acti- 

 vating the human pancreatic secretion, 16 has been the object 

 of intensive study for the past few years. A group of eminent 

 French authors 17 and a number of other investigators 18 have 

 endeavored to determine the real nature of enterokinase ; but 

 opinions arrived at are at wide variance. 19 The belief that 

 the substance is a ferment has met with considerable oppo- 



13 L. Popielski, Zeitschr. f. physiol. Chem., 71, 186, 1911. 



14 E. S. London and C. Schwarz, Zeitschr. f. physiol. Chem., 68, 346, 1910. 



15 E. Gley, Journ. de Physiol., 14, 507, 1912. 



16 Observations of A. Ellinger, M. Kohn, K. Glassner and J. Wohlgemuth. 

 w Dastre, Camus, Delezennes, Frouin, Gley and associates. 



18 Bayliss and Starling, O. Cohnheim, Ciaccio, C. Foa, Hamburger and 

 Hekma, Vernon, E. Zunz. 



19 Literature upon Enterokinase: Th. Brugsch, Handb. d. Biochem., 3', 115- 

 116, 1910; S. Rosenberg, ibid., 3', 127-136, 1910; C. Oppenheimer, Fermente, 

 3d ed., 208-215, 1910; W. Biedermann, Winterstein's Handb. d. vergleich. 

 Physiol., 2', 1409-1415, 1911. 



