FORMATION OF HYDROCHLORIC ACID IN THE FOVEOL^E. 233 



quently found it similarly in the tips of pyloric and duodenal 

 villi, between the epithelial cells and in the subjacent connective 

 tissue. Similar results were obtained in a fowl which had been 

 given subcutaneously 13 c.c. of a 10 per cent, solution of sodium 

 ferryocyanide and 13 c.c. of a 25 per cent, solution of iron and 

 ammonium citrate, and two hours later intravenously 7 c.c. 

 of the sodium ferrocyanide solution and 4.5 c.c. of the iron 

 and ammonium citrate solution; both solutions were fresh and 

 warm. The animal stood these injections very well, although 

 they had some toxic effect. The fcecal passages were liquid and 

 contained a little blue precipitate which became quite heavy and 

 abundant on the addition of hydrochloric acid. The animal was 

 killed in one hour by chloroform, and .pieces of various tissues 

 w r ere fixed in absolute alcohol. When the proventriculus was 

 opened a blue fluid willed out of the openings of the depressions 

 which contain the compound glands; no blue color appeared else- 

 where in this organ. Microscopic examination of paraffine sec- 

 tions showed Prussian blue on the surface of the epithelium 

 lining the necks of the depressions of the surface epithelium 

 into which the glands open and in the lumina of these depressions. 

 It was not within the glands themselves. It was present betw r een 

 the epithelial cells of the region where the depression receiving 

 the secretion of the glands opened on to the surface of the pro- 

 ventriculus and in the subjacent blood vessels and lymphatic 

 spaces. It was abundant in the blood vessels and lymphatic 

 spaces of the muscular coat of the stomach, and of the crop, 

 and of the heart muscle, and of the muscular stomach (gizzard). 

 It appeared also in the epithelium of the intestine and in the 

 connective tissue and muscle of the ccecal diverticula. It was 

 abundant in the liver appearing in theendothelial cells of Kupffer 

 and in the blood vessels. It was absent from the breast muscle 

 and its lymphatic and blood vessels. 



These results, therefore, answer this first question in the 

 affirmative. The Prussian blue reaction appears in many places 

 besides the gastric mucous membrane. In most of them it seems 

 probable that it takes place without the help of an acid. And 

 they show that, if its occurrence on the surface of the gastric 

 mucous membrane is due to the acid formed in the stomach then 



