THE PANCREAS AS AN ENDOCRIN GLAND 715 



perfused aseptically with Locke's solution containing physiologic concen- 

 trations of dextrose there is no alteration of the reducing properties of the 

 perfused solution, but something seems to be added to it that brings about 

 a utilization of the sugar by the living heart to an extent that does not 

 occur with the heart alone. This substance shows some of the properties 

 of an enzyme, and may be identical with the hypothetical internal secre- 

 tion of the pancreas so necessary to sugar metabolism. The experimental 

 evidence suggests that the substance or substances obtained by perfusing 

 the pancreas may be concerned in the normal activity of the pancreas con- 

 cerned with sugar metabolism. 



Jacoby (1916) thinks that diabetes in addition to being a disturbance 

 of metabolism is possibly also a sugar intoxication. True diabetic dis- 

 turbances are due to the hyperglycemia, not only to the metabolic proc- 

 esses through which too much sugar is formed, nor to the loss of sugar- 

 destroying function, but also to the toxic effects of the abnormally long cir- 

 culation of sugar in the blood. Murlin and Kramer noted that the ad- 

 ministration of alkali to* totally and partially depancreatized dogs im- 

 proved the oxidation of glucose. Later Murlin and Graver announced that 

 the treatment of human diabetes with sodium carbonate resulted in dis- 

 tinct clinical improvement in several patients. 



Schafer (1916) regards as the most probable hypothesis the presence 

 of a chalonic or inhibitory agent in the internal secretion of the pancreas 

 which affects carbohydrate metabolism. Provisionally this substance may 

 be called insulins. Whether this is of the nature of an enzyme or an 

 antacoid cannot be definitely stated, although most probably the latter, in 

 accordance with what is known of the other internal secretions. 



Lombroso interprets the fact that the injection of sugar into a dia- 

 betic animal diminishes the glycosuria instead of increasing it, by the 

 hypothesis that sugar stimulates the elaboration of glycolytic enzymes on 

 the part of these organs with which the pancreas collaborates to regulate 

 glycolysis. Murlin and Sweet found that dogs with a previous gastrectomy 

 developed little or no glycosuria upon removal of the pancreas. In such 

 a dog given artificial digestion the general nutrition remained good. In 

 dogs depancreatized after gastrectomy the profound toxemia of a simple 

 pancreatectomy does not occur. They suggest that the pancreatic hor- 

 mone preserves the proper concentration of hydrogen ions in the tissues 

 for combustion of glucose; it may, therefore, be a peculiarly adapted 

 alkali produced by the islands of Langerhans. 



Beifeld, Wheelon and Lovellete found that various pancreatic and 

 salivary gland preparations cause a vascular depression which they ex- 

 plain as due to an augmented irritability of the vasoconstrictor centers. 

 Epstein and Baehr state that after pancreatectomy there are marked 

 changes in blood volume which must be considered in estimating accurately 

 the variation in sugar and other constituents of the blood. After pan- 



