490 DIGESTION. 



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

 has been studied with the aid of a fistula in the intestine according to 

 the method of THIRY and VELLA or of PAWLOW. According to BOLDY- 

 EEFF, 1 in dogs, with an empty stomach, a scanty secretion lasting about 

 15 minutes occurs at regular intervals for about two hours. According 

 to BOLDYREFF the intestinal juice is obtained from a THIRY- VILLA fistula 

 outside of the digestion period without any apparent stimulation. Accord- 

 ing to this experimenter, during gastric digestion the juice is periodically 

 but less abundantly secreted as the time interval is much longer, namely 

 three, four or five hours. Otherwise it is generally admitted that the 

 partaking of food causes the secretion, or if this is continuous, as in 

 lambs (PREGL), it increases the secretion. The researches of DELE- 

 ZENNE and FROUIN show without question that the passage of chyme 

 into the intestine increases the secretion of the intestinal juice. The 

 acid causes a formation of secretin (see below), and this produces, 

 according to the above investigators, a secretion of intestinal juice. 

 Among the chemically active substances causing a secretion we must 

 mention acids in general and gastric juice. Soaps, chloral, ether and 

 on intravenous injection, also intestinal juice or an extract of the intes- 

 tinal mucosa (FROUIN), are chemical excitants of intestinal juice. 

 Several salts, NaCl, Na2SOi, and others, may cause an abundant secre- 

 tion of fluid into the intestine when injected intravenously or subcu- 

 taneously, 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 2 ). 



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 3 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. 



ir Thiry, Wien, Sitz.-Ber., 50; Vella, Molieschott's Untersuch., 13; Boldyreff, 

 Zeitschr. f. physiol. Chem., 50, Centralbl. f.'Physiol. 24, 93 (1910). 



2 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). 



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



