356 THE ADRENAL, GENERAL MOTOR, AND VAGAL SYSTEMS. 



liver and other sugar-producing tissues of the body. What 

 this material is and how it acts has not yet been determined 

 satisfactorily/ 7 That we are dealing with an internal secre- 

 tion is clear, and, such being the case, the secretion probably 

 passes out into the blood by the pancreatic vein, which "opens 

 into the splenic and mesenteric veins." As these open, in turn, 

 in the portal vein, the pancreas would then supply a special 

 ferment for the conversion of glycogen into a functional sugar. 



If the foregoing symptoms are closely scrutinized, it soon 

 becomes apparent that the functions of the pancreas as will 

 be shown in the next chapter are far more important than is 

 generally believed. For the present, however, we will limit 

 our inquiry to the subject in point. 



The fact that, notwithstanding the ingestion of carbo- 

 hydrates, the glycogen will totally disappear from the liver is 

 easily accounted for. A prominent function of the pancreas 

 during intestinal digestion is to transform starches into malt- 

 ose, to insure absorption of this sugar. When the organ is 

 removed, therefore, its amylopsin is no longer furnished to the 

 intestinal contents, starches are not properly converted, and 

 the portal vein carries no maltose to the hepatic lobule. The 

 production of glycogen, therefore, ceases. The fact, however, 

 that we can so easily account for this phenomenon suggests 

 that: 



1. The pancreas is the organ upon which all the preliminary 

 functions connected with the formation of glycogen depend. 



2. Its amylopsin converts starches in the intestine to prepare 

 them for the elaboration of glycogen in the hepatic cell. 



S. Its internal secretion, supplied to the portal system by way 

 of the splenic vein, converts glycogen into dextrose. 



That we are on the right path is suggested by a series of 

 experiments by Croftan, 23 in which the conversion of glyc- 

 ogen into sugar was obtained by means of injections of supra- 

 renal extract: "Incomplete as these experiments are," says 

 the author, "they reveal the fact that the injection of supra- 

 renal extract can cause the excretion of dextrose provided the 

 quantity injected is sufficiently large. Why in the case of one 



Croftan: American Medicine, Jan. 18, 1902. 



