454 DIGESTION. 



and possibly also of a steapsinogen, in the mucous coat has been men- 

 tioned above. 



According to HERZEN and his collaborators l we must differentiate between 

 pepsinogenic and other bodies accelerating the flow of juice. To the first belong 

 mulin and glycogen, while alcohol belongs to the latter class of bodies. Dextrin not 

 only accelerates the flow of juice, but also acts as a pepsinogenic, especially as the 

 latter. Meat extract which has both actions is especially a flow-accelerator. 

 The pepsinogenic action consists in converting the zymogen into pepsin, and in 

 this way increases the quantity of pepsin ; the flow-accelerating substances increase 

 the quantity of secreted juice. 



The question in what cells the two zymogens, especially the propepsin, 

 are produced, has been extensively discussed for several years. Formerly 

 it was the general opinion that the cover cells were pepsin cells, but 

 since the investigations of HEIDENHAIN and his pupils, LANGLEY and 

 others, the formation of pepsin has been attributed to the chief cells. 2 



The Pyloric Secretion. That part of the pyloric end of the dog's 

 stomach which contains no fundus glands was dissected by KLEMENSIE- 

 wicz, one end being sewed together in the shape of a blind sac and the 

 other sewed into the stomach. From the fistula thus created he was 

 able to obtain the pyloric secretion of a living animal. This secretion 

 is alkaline, viscous, jelly-like, rich in mucin, of a specific gravity of 1.009- 

 1.010, and containing 16.5-20.5 p. m. solids. It habitually contains 

 pepsin, which has been proven by HEIDENHAIN by observations on a 

 permanent pyloric fistula, and the amount may sometimes be considerable. 

 CONTEJEAN investigated the pyloric secretion in other ways, and finds 

 that it contains both acid and pepsin. The alkaline reaction of the 

 secretions investigated by HEIDENHAIN and KLEMENSIEWICZ is due, 

 according to CONTEJEAN, to an abnormal secretion caused by the opera- 

 tion, because the stomach readily yields an alklaline juice instead of an 

 acid one under abnormal conditions. The reports of HEIDENHAIN and 

 KLEMENSIEWICZ have nevertheless been substantiated by AKERMANN, 

 KEESTEFF, SCHEMIAKINE and others. 3 



The secretion of gastric juice under different conditions ma} r vary 

 considerably. The statements concerning the quantity of gastric juice 

 secr'eted in a certain time are therefore unreliable. ROSEMANN 4 ob- 

 served on sham feeding in dogs a secretion of 917 cc. in the course of 

 3J hours a considerable quantity. 



The Chyme and the Digestion in the Stomach. By means of the 

 chemical stimulation caused by the food, a copious secretion of gastric 



Pfliiger's Arch., 84. 



See footnote 5, p. 452. 



Heidenhain and Klemensiewicz, 1. c.; Contejean, 1. c., Chapter II, and Skand. 

 Arch f. Physiol , 6, Akermann, ibid., 5; Kresteff, Maly's Jahresber., 30; Schemia- 

 kine Arch, des scienc. biolog. de St. Pe"tersbourg, 10. 



Pfliiger's Arch., 118. 



