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



reaction was found in all places in which it was found in the 

 first rabbit. In addition it was found in the villi of the duodenum 

 appearing in the connective tissue near the free end of the villus, 

 and also between the epithelial cells of the free end of the villus. 

 The blood vessels of the gastric mucosa contained Prussian blue, 

 but in much smaller quantities than did those of the spleen and 

 liver. The parietal cells were practically free of it; there may 

 have been a little, for three or four minute particles were found 

 in the section, but it was impossible to say that these extremely 

 minute particles were not on the surface of the cell instead of 

 within it. 



From these two experiments it is evident that the Prussian 

 blue is precipitated in the blood stream when solutions of these 

 salts are injected into it. It may also be precipitated or absorbed 

 in various places, especially in the endothelial cells of Kupffer 

 in the liver. They show, that it may appear on the surface of 

 the stomach when it is not in the parietal cells; that it appears 

 in the blood vessels and lymphatic spaces before it appears in 

 the parietal cells. Its appearance between the cells of the surface 

 epithelium between adjacent foveolae, and also in the inter- 

 glandular blood vessels and lymphatic vessels beneath this 

 epithelium suggests that the Prussian blue or some or all of the 

 salts necessary for its formation may pass from the surface into 

 the interglandular lymphatics. These results taken in conjunc- 

 tion with those reported by Miss Fitzgerald in her rabbits Nos. 

 5 and 6 suggest very strongly that the Prussian blue or the 

 constituents forming it may pass from the blood vessels into 

 the parietal cells instead of in the reverse direction as she sup- 

 posed. In other rabbits we have frequently seen the Prussian 

 blue in the blood vessels and in only those parts of a few parietal 

 cells lying next to the blood vessels, just as she reports in her 

 rabbits 5 and 6. We have never found it in the parietal cells 

 without finding it also in the blood vessels, but in these two 

 instances we found it in the blood vessels when it was absent 

 from the parietal cells. When it was present on the surface of 

 the stomach we found it uniformly present also between the 

 cells of the interfoveolar surface epithelium and in the inter- 

 glandular lymphatic vessels and blood vessels. We have fre- 



