FORMATION OF HYDROCHLORIC ACID IN THE FOVEOL.^. 23! 



Prussian Blue in Places Other than Gastric Mucous Membrane. 

 -Into the ear vein of a rabbit was injected 13 c.c. of a 10 per cent, 

 solution of sodium ferrocyanide, and into the other ear vein 10 

 c.c. of a 25 per cent, solution of iron and ammonium citrate; both 

 solutions were warm. They were perfectly fresh, having just 

 been made. They did not give a precipitate of Prussian blue 

 when diluted each with an equal quantity of water, one added to 

 the other, and the mixture allowed to stand in a warm chamber 

 at 37 C. for 28 hours. The rabbit show r ed some toxic effects 

 during the injection, rallied temporarily, but died in 20 minutes. 

 The stomach was opened at once. It was full of fresh food in 

 an active state of digestion. Prussian blue appeared in all parts 

 of it, although the lesser curvature seemed to have less of it 

 than the rest of the stomach. Pieces of various tissues were fixed 

 in absolute alcohol. The urine showed both salts present in 

 abundance; the bile contained none of either. The saliva con- 

 tained ferric citrate but no ferrocyanide. The heart's blood 

 showed no blue on the addition of acid nor on the addition of 

 acid w T ith each one of the two salts. Therefore, it did not contain 

 either salt in any quantity appreciable by this method. Parafnne 

 sections were cut and they show r ed the Prussian blue reaction 

 on the surface of the stomach; in the mucous membrane of the 

 stomach appearing in the blood vessels, in the lymphatic spaces, 

 in the epithelium between the foveolae; in the connective tissue of 

 the muscularis mucosae and of the tunica muscularis of the 

 stomach. It did not appear in the parietal cells nor in any 

 other gland cells, nor in the gland lumen. It was found in many 

 other tissues, namely: in the liver, appearing in the blood vessels, 

 in the endothelial cells of Kupffer, and a little in the bile capil- 

 laries; in the spleen appearing in the blood vessels; in the 

 blood vessels of the heart muscle. These were the only places 

 in which we looked for it, but we found it in all of them. 



This experiment was repeated, using smaller quantities of the 

 salts injected subcutaneously on two successive days (a total of 

 1.6 grammes iron and ammonium citrate and 3.0 grammes sodium 

 ferrocyanide well diluted). The rabbit was killed 30 minutes 

 after the second injection; the tissues were fixed in formalin 

 (neutralized with magnesium carbonate). The Prussian blue 



