140 THE DIGESTIVE FLUIDS. 



portion of the mucous membrane contain pepsin in considerable 

 amount. Whether or not a diastatic ferment also is here secreted 

 is as yet undecided, as the secretion can scarcely be obtained uncon- 

 taminated by pancreatic juice, and it is hence difficult to make 

 definite statements regarding its composition. 



THE ENTERIC JUICE. 



The enteric juice is essentially the secretory product of the glands 

 of Lieberkiihn, which are found imbedded in the mucous membrane 

 of the small intestine, and to some extent also in the large intestine. 

 It may be procured by resecting a loop of the intestine, measuring 

 about 0.150.20 meter in length, and closing the proximal end, 

 while the distal end is sutured to the abdominal wall. The mes- 

 entery, however, is allowed to remain, so that the nerve- and blood- 

 supply of the portion which has thus been isolated is interfered with 

 as little as possible. Instead of thus forming a blind pouch, as was 

 first done by Thiry, both ends of the resected loop may also be 

 sutured to the anterior abdominal wall. Such fistula? were first 

 established by Vella, and they accordingly bear his name. The free 

 ends of the divided gut are in either case then united with each 

 other and the abdominal wound closed. 



In animals which have thus been operated it is noted that after 

 five hours following the ingestion of food a copious secretion of 

 fluid takes place in the small intestine, which continues for about 

 six hours. During this period of activity the mucous membrane 

 presents a rose-red color, while it is pale when at rest. As in the 

 case of the pancreas, the secretion is intermittent. It can be mani- 

 festly excited in a reflex manner, as a moderate secretion may be 

 observed within an hour after the ingestion of food that is, at a 

 time when but little chyme has passed into the small intestine. 

 Later, when the food has passed the stomach, its presence alone or 

 that of the digestive products which have been formed already, 

 apparently excites the increased secretion which is then observed. 

 This may be further increased artificially by mechanical and espe- 

 cially by electrical stimulation, and it is indeed possible to cause the 

 secretion of enteric juice in this manner even at a time when diges- 

 tion is not going on. 



In the upper portion of the duodenum of the dog the secretion is 

 said to be small in amount, mucoid, and jelly-like, while further on 

 it becomes more fluid. 



As obtained, the enteric juice always contains a not inconsiderable 

 amount of mucus, which is derived from the goblet-cells that are 

 found along the entire length of the intestinal canal. The small 

 amorphous flakes which are always found in the secretion consist 

 entirely of mucus. The juice itself, which can be separated from 

 the greater portion of the mucus by filtration, is in the lower por- 

 tion of the small intestine a thin light-yellowish fluid, of a strongly 



