CHAP. II.] FUNCTION OF THE BORDER CELLS. 109 



the border cells of the stomach were coloured of a dark colour by perosmic 

 acid, whilst the chief cells were not, and explained the reaction by sup- 

 posing that the coloured particles consist of ferment, because solutions of 

 enzymes are similarly darkened. The views of Nussbaum on this matter 

 may be set down as undeserving of serious discussion. 



Although we may then hold it as proved that the formation of 

 acid in the gastric juice is associated with the border cells, direct 

 observations would appear to shew that in the deeper part of the 

 gastric glands the reaction is never acid, and that it is so only on the 

 surface of the stomach and near the mouths of the glands. 



Claude Ber- If a solution of lactate of iron and ferrocyanide of 

 "rrt' 8 ? P tii~ P otass ^ um be mixed, no blue colour is produced except 

 reaction'of the nen a ^ ree ac id be added. As these salts do not 

 mucous mem- exert any poisonous action, it occurred to Claude 

 brane of the Bernard 1 to inject their solutions into the blood and 

 stomach. to no ti c e what structures in the stomach, if any, 



would assume a blue colour. It was found that the surface of the 

 stomach was stained of a Prussian-blue colour, but that the deeper 

 portions of the mucous membrane were unstained. 



Similarly it has been found that whilst the surface of the 

 mucous membrane has an acid reaction, on making sections parallel 

 to the surface, so as to cut the glands at some distance from their 

 mouths, the exposed surface is not acid. This experiment is unworthy 

 of serious discussion, seeing that lymph, blood, and the cells them- 

 selves would all tend to neutralise the extremely small amount of 

 acid present in the glandular lumina. 



Observations have likewise been made with a view to determine 

 whether the border cells have an acid reaction, but with entirely 

 negative results 2 . 



Are we from these observations to conclude that whilst the 

 border cells of the glands of the fundus are essential to the production 

 of the free acid of the gastric juice, they are not the actual seats of 

 its formation, and that it is only on the free surface of the mucous 

 membrane of the stomach that acid is liberated ? Even Claude 

 Bernard hesitated to draw this inference from his experiment. It is 

 not only conceivable, but probable, that, so soon as formed, the acid 

 secretion of the gastric glands is poured into the stomach, so 

 that no appreciable quantity of acid is retained in the gland, able 

 to give an obvious colour reaction in the deeper part of the mucous 

 membrane. This explanation does not account for the undoubted 

 failure to prove that the border cells have an acid reaction ; but the 



1 Claude Bernard, Lemons sur les proprietes physiologiques et les alterations patholo- 

 giques des liquides de Vorganisme. Paris, 1859, Vol. n. p. 375. 



2 Lepine, 'Recherches experimentales sur la question de savoir si certaines cellules 

 des glandes (dites a pepsine) de 1'estomac presentent une reaction acide.' Gazette 

 medic, de Paris, 1873, p. 689. Heidenhain, see 'Die Bildung der Saure des Magen- 

 saftes.' Hermann's Handbuch, Vol. v. Part i. p. 150 (small type). 



