530 LECTURE XXII. 



deep significance is to be ascribed to the intestine in the general metabolism 

 of the organism. 



We have up to this point merely considered the pancreatic juice as such, 

 and, with the exception of its alkali content, have paid little attention to 

 the secretion of its individual ferments. We have seen that trypsin and 

 steapsin are secreted as zymogens, while for the diastase arguments have also 

 been advanced, though probably wrongly, in favor of a zymogen condition. 

 The knowledge of the fact that the two first-named ferments exist in two 

 states, was of great importance for subsequent investigation, and above 

 all it was very significant that trypsinogen was activated by a constituent 

 of the intestinal fluid, namely enterokinase. In introducing pancreatic 

 fistulae, usually the entrance point of the principal duct from the pancreas 

 into the duodenum is sought, and then the papillae, together with the piece 

 of intestinal membrane bearing it, is cut out from the alimentary canal and 

 sewed into the wound in the body. If the pancreatic juice flowing through 

 such a fistula be examined, it will be found that it is always active. This 

 is due to the fact that the pancreatic juice thus obtained is always mixed 

 with some secretion from the piece of intestine. If it be desired to obtain 

 the pancreatic juice in an inactive condition, this little piece of intestinal 

 membrane must be removed completely. 1 It has been found that even 

 such juice, under certain conditions, may contain, besides the zymogens, 

 active ferments as well. Thus we know that by the introduction of acid 

 and of soaps into the intestine a juice more or less rich in active ferments 

 results. Again, in the case of nourishment with a mixed diet, there 

 is obtained a varying amount of active ferments, the quantity depending 

 upon the nature of the food. 2 When meat is eaten, for example, the 

 largest amount of zymogens is obtained, while the least amount results 

 from a milk diet. Bread occupies an intermediate position. 



Before the fact was known that the pancreatic ferments are, for the 

 most part, given up in the form of zymogens, and that these are activated 

 by the intestinal juices, it was considered as proven that each food caused 

 the production of all three ferments, but that the fat-splitting ferment 

 was present in largest amount. As Babkin has shown, this specialization 

 does not take place. The three principal ferments of the pancreatic juice 

 are, under physiological conditions, secreted practically evenly. If the 

 value of the pancreatic juice obtained after eating a certain kind of food 

 is based upon the amount of proteolytic ferment the juice contains, it is 

 found that milk produces a secretion of greatest digestive power. The 

 two other ferments, diastase and steapsin, are likewise present in consid- 

 erable amount. The activity of these two ferments remains in this case 



1 B. P. Babkin: Ber. kaiserl. militararztl. Akad. zu St. Petersburg 9, Nos. 2 and 3, 

 93 (1904). 



3 Babkin: ibid. 11, Nos. 2 and 3, p. 93 (1904). 



