474 DIGESTION. 



The conversion of the trypsinogen into trypsin in the removed gland or 

 in an infusion under the influence of air and water and also by other bodies 

 has been known for a long time. According to VERNON the trypsin 

 itself has a strong activating action upon trypsinogen, and in this regard 

 it is more active than enterokinase. The correctness of this statement 

 is still denied by BAYLISS and STARLING and by HEKMA. The ordinary 

 view of HEIDENHAIN, that the transformation of trypsinogen into trypsin 

 is also brought about by acids, has been found to be incorrect by HEKMA. 1 

 Besides the enterokinase and the micro-organisms, there are other activa- 

 tors of the trypsinogen, namely liver-press-juice (WOHLGEMUTH 2 ) and 

 certain amino-acids and finally, as first shown by DELEZENNE and then 

 by ZUNZ by further investigations, especially the lime salts. 3 These last 

 do not act immediately, but only after some time, for example, a couple 

 of hours, and then they activate suddenly. The lime salts are not neces- 

 sary for the digestive action of the juice, and when the activation 

 has once taken place, they can be removed without any harm. They 

 probably have a similar action as in the coagulation of the blood. Accord- 

 ing to DELEZENNE the lime salts have the same importance in the activa- 

 tion of the rennin-zymogen of the juice as in the activation of the trypsino- 

 gen. This enzyme is .also activated by enterokinase. 



The way in which the trypsinogen is converted into trypsin is still 

 unknown and is the subject of dispute. According to one view, proposed 

 by PAWLOW and defended by BAYLISS and STARLING, the trypsinogen is 

 transformed into trypsin by the action of the kinase. In the opinion of 

 DELEZENNE, DASTRE, and STASSANO, and others, 4 the trypsin, on the 

 contrary, is a combination of the kinase and trypsinogen, analogous to 

 the haBmolysins, which according to EHRLICH'S side-chain theory are 

 combinations between a complement and an amboceptor. 



The specific excitants for the secretion of pancreatic juice are, accord- 

 ing to PAWLOW and his collaborators, acids of various kinds hydro- 

 chloric acid as well as lactic acid and fats, the latter acting probably 

 by virtue of the soaps produced therefrom. Alkalies and alkali carbonates 

 have, on the contrary, a retarding action. It appears that the acids act 

 by irritating the mucosa of the duodenum. Water, which causes a secre- 

 tion of acid gastric juice, likewise becomes, indirectly, a stimulant for the 



by Bierry, Compt. rend., 140, and Compt. rend. soc. biolog., 58, and Plimmer, Journ. 

 of PhysioL, 34. 



1 Vernon, Journ. of PhysioL, 28; Hekma, Kon. Akad. v. Wetenschappen te 

 Amsterdam, 1903, and Arch. f. (Anat. u.) Physiol., 1904; Bayliss and Starling, Journ. 

 .of PhysioL, 30. 



2 Bioch. Zeitschr., 2. 



3 Delezenne, Compt. rend. soc. biol., 59, 60, 62, 63; Zunz, footnote 2, p. 473. 



4 Bayliss and Starling, Journ. of PhysioL, 30 and 32, which also cites the other 

 investigators. See also footnote 1, p. 472. 



