5 34 ME CHA NISM OF SE CRE TION OF GA S TRIC JUICE. 
This he cut across, and tested the reaction of the fluid in its cavity. He 
found it as strongly acid as the secretion inside the stomach cavity. 
This experiment may be taken to show that the acid is secreted in the 
glands, but is continually being carried away by the stream of secretion. 
It might be objected against this experiment, that the fluid in the cavity 
of the compound gland is in communication with the stomach cavity 
and is acid by reason of admixture, but the communicating duct is too 
small to make this probable; moreover, there must be a continual 
stream flowing during secretion in the opposite direction from gland 
cavity to stomach cavity. That the gland cavity is not passively filled 
with secretion from the general stomach cavity, is also shown by the 
fact that some of these glands are swollen out with secretion while 
others are empty. It may be taken, then, that the gastric juice is acid 
as secreted by the gland-cells, and does not first become acid in the 
stomach. 
Such observations as have been made in order to ascertain whether 
the border cells yield an acid reaction have not been successful. 
Though the mass of evidence is very greatly in favour of the view that 
the border cells are the origin of the acid of the juice, there are not 
wanting those who deny it entirely. Contejean x observed, as had 
previously been shown by Langley, 2 that the stomach cells of the frog, 
although they secrete acid, also secrete pepsin. But a more remarkable 
statement is that the pylorus cells secrete an acid juice. This is so 
much at variance with the results of the majority of investigations, that 
it cannot lie accepted as correct. If it were true, a conclusive proof 
would be furnished against the view that the border cells originate the 
acid. 
As regards the functions. of the different regions of the stomach, it 
may be stated that the fundus and the greater curvature form in most 
animals pepsin, hydrochloric acid, and other constituents of the gastric 
juice. But considerable discussion has taken place as to the functional 
importance of the pyloric region. That an extract can lie made from 
the pyloric region containing pepsin is generally agreed, but such an 
extract, in comparison with one prepared from the rest of the stomach, 
has very small digestive value. Langley, 2 in one experiment on the 
mucous membrane of the mole, found that if the digestive power of 
the pyloric region be taken as 1, that of the fundus would be 73. 
What then is the source of the pepsin that can be obtained from 
the pyloric mucous membrane ? Is it pepsin formed by the gland 
cells in the pyloric region, or is it absorbed pepsin that has 
passed with the absorbed food into the mucous membrane of this 
region ? 
\Yassmann r ' and v. Wittich 4 have held that the pepsin was merely 
infiltrated pepsin, and Wassmann stated that it was removable by 
repeated washing with water. On the other hand, Ebstein and 
Griitzner 5 found that washing the mucous membrane of the pylorus 
causes but a very slow loss of pepsin. If, then, the cells of the mucous 
1 "Contribution a l'etude ile la physiologic de l'estomac," CentraZbl. f. riiysiol., 
Leipzig u. Wien, 1892. 
2 Proc. Boy. Soc. London, 1881, No. 212. 
3 " De digestione nonnulla.'" Berolini, 1S39. 
4 "Ucber die Pepsinwirkung der Pylorusdrusen," Arch. f. d. ges. Physiol., Bonn, 1873. 
Bd. vii. 
5 "Ueber den Ort der Pepsinbildung in Magen," ibid., 1872, Bd. vi. 
