226 B. C. H. HARVEY AND R. R. BENSLEY. 



chloric acid is being actively formed on the surface of the mucous 

 membrane. 



In the first part of this paper we shall examine very briefly the 

 evidence which has led some to think that free hydrochloric 

 acid is formed in the parietal cells. We shall consider especially 

 the Prussian blue reaction, which, as used by Miss Fitzgerald 

 ('io), has given by far the most definite results. We shall 

 report some results which we have obtained by this method, 

 which in connection with those reported by her show that this 

 reaction does not prove the presence of free hydrochloric acid 

 in the gastric glands under normal conditions. 



In the second part of the paper we shall show that the contents 

 of the parietal cells and of the lumina of the gastric glands are 

 not acid but neutral or alkaline, even when hydrochloric acid 

 is being actively formed on the surface of the mucous membrane. 



FACTS WHICH HAVE SUGGESTED SOME ASSOCIATION BETWEEN 



THE PARIETAL CELLS AND THE HYDROCHLORIC ACID 



OR ITS ANTECEDENTS. 



Heidenhain ('70), Langley ('81) and others were able to asso- 

 ciate other secretory functions of the gastric mucous membrane 

 very definitely with other cells. This left the parietal cells and 

 the formation of hydrochloric acid. Further, Miss Greenwood 

 ('85), and afterward Macallum ('08) and Miss Fitzgerald ('io), 

 have show r n that chlorides are more abundant in the parietal 

 cells than in other parts of the gland. These facts suggest that 

 there is some association between the formation of the hydro- 

 chloric acid and the parietal cells. They leave the question 

 quite open, however, as to where the free hydrochloric acid is 

 first formed as such. The parietal cells probably form substances 

 which later furnish the chlorine of the hydrochloric acid, but our 

 results appearing in the second part of this paper show that these 

 cells do not normally contain the hydrochloric acid itself. 



Miss Fitzgerald ('io) employed the Prussian blue reaction and 

 obtained very definite results which must be carefully considered 

 in the decision of this question. She found the Prussian blue 

 deposited in the canaliculi of some parietal cells. It will be 

 worth while to examine this reaction and the varying results 

 which have been obtained with it. 



