152 THE DIGESTIVE FLUIDS. 



Maltase, The presence of maltase in the pancreatic juice has 

 been inferred from the fact that small amounts of glucose are 

 invariably formed during the action of the aqueous or glycerin 

 extract of the gland upon starch. Glassner, however, notes that in 

 his case of pancreatic fistula an inversion of maltose to glucose 

 could not be observed (see above). 



Chymosin. Chymosin can be demonstrated by adding a small 

 amount of the pancreatic juice of the ox, pig, or sheep to milk, 

 when coagulation results, as in the case of the chymosin of the 

 gastric juice. The ferment, however, is not present in all mammals ; 

 in dogs and in the human being (Glassner) it is absent. 



THE SECRETION OF THE GLANDS OF BRUNNER. 



In some animals, such as the rabbit, a secretion analogous to that 

 of the pancreas is furnished also by the glands of Brunner, which 

 are found in the upper portion of the duodenum. But in other 

 animals, such as the dog and the pig, the function of these glands 

 is comparable to that of the pyloric glands of the stomach. The 

 reaction of the secretion in the dog is alkaline ; the specific gravity 

 1.0051.020. The amount secreted does not materially exceed 1 

 c.c. per hour, and is not influenced by the state of digestion or the 

 character of the food. Ponamorew found that in the dog the fluid 

 only digested albumin, after being acidified. This observation 

 agrees with the results obtained by Grutzner and others. Glassner, 

 however, states that both in the dog and the pig the proteolytic 

 ferment will digest albumins not only in the presence of acids (0.2- 

 0.3 per cent, hydrochloric acid) but also with a neutral and feebly 

 alkaline reaction (0.5 per cent, sodium carbonate). Pawlow re- 

 gards the ferment as identical with that of the pyloric glands, viz., 

 as pepsin. 



A diastatic ferment does not occur in the secretion of Brunner's 

 glands, but a milk-coagulating ferment is apparently present. 



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 0.15-0.20 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 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 fistulas were first established 

 by Yella, and they accordingly bear his name. The free ends of 



