154 THE DIGESTIVE FLUIDS. 



Enteric juice contains small amounts of an albumin which is 

 coagulated only with difficulty and which has commonly been 

 regarded as a mucin. It appears, however, that the substance is in 

 reality a nucleo-albumin (Kutscher), and that pure enteric juice 

 contains no mucin. 



Of the amount of enteric juice which is secreted under normal 

 conditions in twenty-four hours we know but little. In the intestinal 

 juice of a patient with an intestinal fistula Hamburger and Hekma 

 found a daily secretion of 50125 c.e., with an average of 88 c.c. 

 The amount was the largest from the fourth to the seventh hour 

 following the principal meal of the day. Mechanical stimulation 

 more than doubled the flow. In disease, and notably in Asiatic 

 cholera, exceedingly large quantities may be observed ; but in such 

 cases we are no doubt dealing with a direct transudation from the 

 blood, and not with an actual secretory product of the cells. On 

 section of the corresponding nerves hypersecretion can be artificially 

 brought about. This may be compared to the paralytic saliva which 

 is obtained from the sublingual gland on section of the chorda and 

 of the sympathetic fibres that supply the gland. 



Of ferments, the enteric juice contains invertin, ptyalin, rnaltase, 

 lipase, and in sucklings lactase. While practically all the digest- 

 ive ferments are thus represented, their functional value is here prob- 

 ably insignificant when compared with the presence of three other 

 substances which are of fundamental importance. The one is 

 the enterokinase to which I have already referred on several occa- 

 sions, which activates the trypsin of the pancreatric juice. The 

 other is the so-called erepsin of Cohnheim, which is characterized 

 by the fact that it is incapable of splitting albumins to albumoses, 

 but causes the further cleavage of the latter to amino-acids. In ad- 

 dition, the mucosa of the duodenum and jejunum contains a sub- 

 stance which, when treated with hydrochloric acid and injected into 

 the circulation, causes a secretion of pancreatic juice. The inactive 

 principle is termed prosecretin and its active form secretin. 



Enterokinase. The enterokinase itself has no digestive? power ; 

 it merely activates the trypsin of the pancreatic juice, viz., it trans- 

 forms the inactive zymogen into the active enzyme. Very interest- 

 ing is the fact that the secretion of the kinase can only be effected 

 by the introduction into the intestinal lumen of normal pancreatic 

 secretion. Boiled pancreatic juice, purely mechanical stimulation, 

 as also the injection of pilocarpin, only give rise to the secretion of 

 an enteric juice, which is free from kinase. The kinase is destroyed 

 by a temperature of 67 C. Hamburger and Hekma were able to 

 demonstrate the presence of enterokinase in the enteric juice of man, 

 and ascertained that the substance is not capable of activating in- 

 definite quantities of pancreatic juice, but that a certain quantity of 

 enteric juice can only activate a definite amount of pancreatic juice ; 

 they conclude that enterokinase is not a ferment, and propose to term 

 the substance zymolysin. 



