532 MECHANISM OF SECRETION OF GASTRIC JUICE. 
At the pyloric end of the dog's stomach in the resting or exhausted 
state, an appearance is seen which consists of small and obscure granules 
somewhat radially arranged, an appearance which hears a slight resem- 
blance to that seen in the ducts of salivary glands in the fresh condition. 
A very marked difference exists, however, between the pyloric cells and 
the cardiac cells, and there seems little doubt that considerable histo- 
logical distinction obtains. Nevertheless, attempts have been made by 
Ebstein x and others to prove the identity of the chief cells of the cardiac 
end with the lining cells of the body of the pyloric glands. It may lie 
stated that Langley and Sewall found no difference in the pyloric cells 
whether the glands were in a resting or active condition, and other later 
observations also show a marked uniformity of appearance in the cells 
whatever the secretory condition be. 
It may then be regarded as established that a diminution in the 
amount of granules characterises the chief cells as digestion advances. 
It has, moreover, been shown by Griitzner 2 and others, that as digestion 
advances the fundus glands contain less ferment than in hunger. It is 
therefore justifiable to conclude that the granules are in some way 
connected with the ferment. In addition to this, we have the fact that 
more pepsin can be obtained from the cells of the fundus in the rabbit 
than from the greater curvature, and it is in the fundus that the cells 
are conspicuously granular. We have, however, to consider that, though 
the chief cells will yield pepsin, yet they do not actually contain pepsin. 
If the granules then are connected with pepsin, it must be in some 
antecedent form. The probable explanation of this is that the granules 
of the chief cells consist wholly or in part of pepsinogen, the precursor 
of pepsin. 
The functions of the different forms of cells and of the different 
regions of the stomach.— Heidenhain originated the view that the 
chief cells were connected with the formation of pepsin, and the border 
cells with the formation of the acid of the gastric juice. The arguments 
upon which these conclusions are based are not direct, but though really 
inferential they appear to be supported by such evidence that but little 
doubt can be placed upon their accuracy. 
The reasons for regarding the chief cells as connected with the 
formation of pepsin have been dwelt upon in the previous section. But 
is there evidence to disconnect the border cells from this same function ? 
The most direct evidence we have is that, in the rabbit, the greater 
curvature contains more border cells than any other portion of the 
stomach ; the pyloric glands of the smaller curvature contain at most an 
occasional border cell here and there, yet the amount of pepsin produced 
by the two gland forms is scarcely different. The obvious conclusion is 
that the border cells do not form the ferment. On the other hand, it is 
noticed that the pyloric secretion is distinctly alkaline if separated from 
the rest of the stomach ; this is affirmed by Klemensiewicz, 3 Heidenhain, 4 
and, later, Ackermann. 5 Apparently, therefore, such cells as are present 
1 Arch./, mikr. Anat., Bonn, 1870, Bd. vi. 
- " Untersnch. ueber d. Bildnng n. Ausscli. des Pepsins," Breslan, 1875. 
3 "Ueber den Succns pyloricus," Sitzungsb. d. k. Akad. d. JVissensch. , Wien, 1875, 
Bd. lxxi. 
4 "Ueber die Pepsinbildung in den Pylorusdruseu," Arch. f. d. ges. Physiol, Bonn, 
1878, Bd. xviii. 
6 " Experinientelle Beitrlige zur Kenntniss des Pylorussecretes beirn Hunde," Skandin. 
Arch./. Physiol., Leipzig, 1S94, Bd. v. 
