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 bears 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 

 Ebsteiii l 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 be 

 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. Heidenhaiii 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. f. mikr. Anat., Bonn, 1870, Bd. vi. 



"Untersuch. ueber d. Bildung u. Aussch. des Pepsins," Breslau, 1875. 

 3 "Ueberden Succus pyloricus," Sitzungsb. d. k. Akad. d. Wissenxch., Wien, 1875, 

 Bd. Ixxi. 



"Ueber die Pepsinbildung in den Pylorusdriisen," Arch. f. d. ges. PhysioL, Bonn, 

 1878, Bd. xviii. 



5 " Experirnentelle Beitrage zur Kenntniss des Pylorussecretes beim Hunde," Skandin. 

 Arch.f. Physiol., Leipzig, 1894, Bd. v. 



