110 THEORIES OF SECRETION OF ACID. [BOOK II. 



absence of an acid reaction does not militate against the theory that 

 they are in reality the acid-forming cells of the stomach. As has 

 been justly remarked 1 , a secreting cell does not necessarily contain 

 the products which are characteristic of its activity, and which it 

 contributes to the secretion, and which appear in some cases to be 

 at once removed from their place of origin : thus the hepatic cells 

 contain no bile-colouring matter, and no bile acids ; though unques- 

 tionably these bodies are formed first in those secreting cells. 



To summarize. All the evidence which we possess points to the 

 border cells which are found in certain of the gastric glands, as the 

 seats of the formation of the free acid of the gastric juice ; and the 

 value of this evidence is not diminished by the fact that the cells 

 which are supposed to possess this power possess no acid reaction, 

 inasmuch as other undoubted cases are known in which the pro- 

 ducts of secretion cannot be discovered in the gland cells which form 

 them. 



THEORIES AS TO THE MODE OF PRODUCTION OF THE ACID OF 

 THE GASTRIC JUICE. 



Various attempts have been made to explain the nature of the 

 chemical operations which may lead to the separation of hydrochloric 

 acid by the gastric glands. 



That the acid is derived from the decomposition of chlorides may 

 be assumed, and the assumption is confirmed by the observation of 

 Griitzner, that coincidently with the greatest richness in pepsin of the 

 gastric mucous membrane it is likewise richest in chlorides 2 . 



It was further observed in the first instance by Bence Jones, 

 and afterwards confirmed by Roberts and by Maly, that during active 

 digestion when the gastric juice is being abundantly poured out 

 there is a diminution in the acidity of the urine, which may become 

 neutral or alkaline. 



Bnicke's Briicke 3 surmised that under the influence of their 



hypothesis. secretory nerves the gastric glands possessed the 

 power of decomposing chlorides electrolytically (?), and of directing the 

 hydrochloric acid to the stomach, whilst the bases, accumulating in 

 the blood, were excreted by other channels. 



Eaife's ex- Dr Ralfe 4 gave some support to the electrolytic 

 pertinents. hypothesis by shewing that when a weak current of 



1 Heidenhain, Op. cit., p. 150. 



2 Griitzner, Neue Untersuchungen iiber die Bildung und Ausscheidung des Pepsin. 

 Breslau, 1875, p. 52. 



3 Briicke, Sitzungsber. d. Wiener Akad., Vol. xxxvn. (1859), p. 131, also Vorlesungen 

 iiber Physiologic, Wien, 1875, p. 299. 



4 Kalfe, Lancet, 1874, 2, 29. 



