466 DIGESTION. 



show without question that the passage of chyme into the intestine increases 

 the secretion of the intestinal juice. The acid causes a formation of secre- 

 tin (see below), and this produces, according to the above investigators, 

 a secretion of intestinal juice. As the secretin undoubtedly also increases 

 the secretion of pancreatic juice and as this latter, according to PAWLOW, 

 by its action upon the intestine excites a secretion of intestinal juice, 

 it is difficult to understand why, according to BOLDYREFF, the secretion 

 of intestinal juice should be so weak during the entire gastric diges- 

 tion, sometimes so weak that little if any juice is secreted. Soaps, 

 chloral, ether and on intravenous injection, also intestinal juice or an 

 extract of the intestinal mucosa (FROUIN), are chemical excitants of 

 intestinal juice. Several salts, NaCl, Na2SC>4, and others, may cause 

 -an abundant secretion of fluid into the intestine when injected intra- 

 venously or subcutaneously, as well as after direct application to the 

 peritoneal surface of the intestine. This action can be arrested by the 

 antagonistic, inhibiting action of a lime salt (MACCALLUM). Pilocarpine, 

 which has the power of increasing the activity of secretions, does not 

 increase the secretion in lambs, and in dogs it does not seem to be always 

 active (GAMGEE J ). 



Mechanical irritation of the intestinal mucosa increases the secre- 

 tion in dogs (THIRY) as well as in man (HAMBURGER and HEKMA), but 

 it is still doubtful whether we here have a perfectly physiological juice. 

 In the cases observed by HAMBURGER and HEKMA 2 the flow of fluid was 

 greatest at night as well as between five and eight o'clock in the after- 

 noon, and was lowest between two and five o'clock in the afternoon. 

 The quantity of this secretion in the course of twenty-four hours has 

 not been exactly determined. 



According to DELEZENNE and FROUIN, if any mechanical irritation 

 is prevented, the fluid flowing spontaneously from a fistula in a dog 

 is ten times more abundant in the duodenum than that in the middle 

 or lower part of the jejunum. In the upper part of the small intestine 

 of the dog, on the contrary, this secretion is scanty, slimy, and gelatinous ; 

 in the lower part it is more fluid, with gelatinous lumps or flakes (Ron- 

 MANN). Intestinal juice has a strong alkaline reaction toward litmus, 

 generates carbon dioxide on the addition of an acid, and contains (in 

 dogs) nearly a constant quantity of NaCl and Na 2 CO 3 , 4.8-5 and 4-5 

 p. m. respectively (GUMILEWSKI, RoHMANN 3 ). The intestinal juice 

 of the lamb corresponded to an alkalinity of 4.54 p. m. Na 2 CO 3 . It 



1 Delezenne and Frouin, Compt. rend. soc. biol., 56; Frouin, ibid., 56 and 58; 

 MacCallum, University of California Publications, 1, 1904; Gamgee, Physiol. Chem- 

 istry, 2, 410 (literature). 



2 Journ. de Physiol. et d. path, gen., 1902 and 1904. 



3 Gumilewski, Pfliiger's Arch., 39, Rohmann, ibid., 41. 



