242 



THE GASTRIC JUICE. 



1002-5 (dog, 1005), and it contains only | per cent, of solid constituents. The 

 quantity secreted in 24 hours was estimated by Beaumont, from observations upon 

 Alexis St Martin, who had a gastric fistula (1834) at only 180 grms. daily (!); by 

 Grunewald (1853), in a similar case, as equal to 26*4 per cent, of the body-weight; 

 while Bidder and Schmidt (from corresponding observations on dogs) estimated it as 

 equal to 6 J kilos, daily, corresponding to -^ of the body- weight. It contains: 

 (1) Pepsin, the characteristic hydrolytic ferment or enzym, which dissolves 



Fig. 182. 



Vertical section of the gastric mucous membrane. g,g, pits on the surface ; p, neck of a fundus- 

 gland opening into a duct, g ; x, parietal, and y, chief cells ; a, v, c, artery, vein, capil- 

 laries ; d, d, lymphatics, emptying into a large trunk, e. 



proteids. E. Schutz obtained 0*41 to 1*17 per cent, from a fasting person by 

 means of the oesophageal sound. 



(2) Free hydrochloric acid (Prout, 1824), 0'2 to 0-3 (Bichet, 0-8 to 2*1) per 

 1000; (in the dog, 0-52 per cent.). It occurs free, as the gastric juice always con- 

 tains more free chlorine than bases, to which it can be united (C. Schmidt). Lactic 

 acid is usually met with, but it arises from the fermentation of the carbohydrates 

 of the food. 



Tests. Free hydrochloric acid is detected by the following reactions : 0*025 per cent, solu- 

 tion of mythyl-violet becomes blue ; or alkaline solution of oo-tropaeolin becomes lilac ; or, red 



