SALIVARY GLANDS, STOMACH AND INTESTINES 741 



one follows the intravenous injection and none the oral administration. 

 The negative result, after the oral administration, cannot be due to 

 destruction by pepsin in the stomach, as is evident from the studies by 

 Luckhardt, Keeton, LaMer and Koch (1920). It may be destroyed in the 

 intestines, however. Apparently the substance reaches the gastric cells 

 Immorally, if it really is a physiological process. When introduced 

 through the femoral vein it causes a sudden expulsion of juice which is 

 small in amount. This suggests that the substance is destroyed rather 

 rapidly and probably in the venous system, or between the veins and 

 arteries. Bickel (1917) reports that when he injected the spinach se- 

 cretin by the femoral vein, both a secretion and a fall in blood pressure 

 followed, but that when introduced directly into the mesenteric vein only 

 the fall in blood pressure is observed. Djenab (1917) reports similar 

 results with both spinach and duodenal secretin solutions, and he suggests 

 that the liver neutralizes or destroys the active substance. It is barely 

 possible that these observations explain in part how it is that the liver 

 tissue varies so from time to time in gastrin content. Complete vagotomy, 

 although it diminishes the secretion, does not prevent it. In Pawlow 

 pouch dogs, the stimulating action of gastrin may be arrested by a definite 

 dose of atropin, but it requires a greater dose to prevent secretion after 

 gastrin than after or with a meal. All of these results suggest that the 

 substance acts directly upon the cells and not on the nerve endings only. 



General Conclusions and Clinical Application. It is obvious that 

 unless we obtain these substances in pure form we cannot hope to make 

 an accurate, pharmacological and therapeutic analysis thereof. The 

 purest extracts thus far prepared undoubtedly still contain considerable 

 impurities, some of which may be responsible for certain general physio- 

 logical reactions. The experimental studies by no means prove the endo- 

 crine function of the gastric glands, and there is no physiological evidence, 

 at present, that a substance, gastrin, is normally elaborated in the usual 

 physiological processes in the stomach mucous membrane. That being the 

 case, there is no real organotherapeutic basis for the use of gastrin prep- 

 arations in gastric disturbances. The author does not know of any clinical 

 use of gastrin extracts, but, if it is to be employed at all, it should be 

 injected intramuscularly or subcutaneously ; by mouth it is worthless, and 

 intravenously it is very dangerous, due to the marked depressor action. 



Intestinal Endocrine Function 



In 1896 Popielski first showed that the introduction of 0.4 to 0.5 per 

 cent hydrochloric acid into the duodenum causes a flow of pancreatic juice. 

 This was interpreted by him to be due to a stimulation of nerve endings 

 in the duodenum and thus the secondary stimulation of the pancreas. 



