DIGESTION. 197 



III. The Glands of the Mucous Membrane of the Intes- 

 tines and their Secretions. 



The Secretion of Brunner's Glands. These glands are partly 

 considered as small pancreas glands and partly as mucous or 

 salivary glands, but according to GRUTZNER they are related to the 

 pyloric iglands. They are assumed to contain pepsin (GRUTZNER 

 and diastatic enzymes (COSTA, BUDGE and KROLOW). The diffi- 

 culty of collecting the secretions of these glands free from contami- 

 nation, however, makes these assumptions somewhat unreliable. 



The Secretion of Lieberkuhn's Glands. The secretion of these 

 glands has been studied by the aid of a fistula in the intestines 

 according to the method of THIRY and VELLA. Very little if any 

 secretion takes peace in fasting animals (dog) when the mucous 

 membrane is not irritated. The secretion begins in the first hour 

 .after partaking of food, but the maximum varies with the quantity 

 and character of the food (HEIDEKHAI^). Mechanical, chemical, 

 or electrical irritation excites a secretion or increases that already 

 begun (THIRY). Laxatives do not increase the secretion, while 

 pilocarpin produces a very abundant one (MASLOFF and VELLA). 

 The quantity of this secretion in the course of 24 hours has not 

 been exactly determined. 



In the upper part of the small intestines of the dog this secre- 

 tion is scanty, slimy, and gelatinous; in the lower part it is more 

 fluid, with gelatinous lumps or flakes (ROHMANN). Intestinal 

 juice has a strong alkaline reaction, generates carbon dioxide on 

 the addition of an acid, and contains (in dogs) nearly a constant 

 quantity of NaCl and Na 2 C0 3 , 4.8-5 and 4.5 p. m. respectively 

 (GuMiLEWSKi, ROHMAITN). It contains albumina (THIRY found 

 8.01 p. m.), the quantity decreasing with the duration of the elimi- 

 nation. The quantity of solids varies. In dogs the quantity of 

 solids is 12.2-24. 1 p. m., and in sheep 46-47 p. m. The specific 

 gravity of the intestinal juice of the dog, according to the observa- 

 tions of THIRY, is 1.010-1.0107. 



The action of intestinal juice has not been exhaustively studied 

 and the opinions concerning it are somewhat at variance. According 

 to most investigators, starch is converted into sugar, a statement 



