THE PANCREAS AS AN EKDOCRIN GLAND 717 



nicotine become variable. Their observations do not support the theory 

 that the pancreas exerts a depressing influence upon the sympathetic 

 nervous system. Meltzer and Kleiner conclude that the sugar production 

 following the intraperitoneal injection of adrenalin is not of pancreatic 

 origin but most probably the result of its action upon the celiac ganglia 

 or adrenals. The greater production of sugar resulting from painting 

 with adrenalin of the unisolated pancreas is due to the escape of a large 

 part of the adrenalin into the peritoneal cavity. 



De Corral states that electrical stimulation of the vagus below the 

 cardiac branches and after destruction of the hepatic branches causes a 

 diminution of blood-sugar. This diminution occurs so rapidly that it 

 must be assumed that the internal secretion of the pancreas at least in- 

 creases the consumption of sugar in the tissues or in the blood. This takes 

 place in normal conditions or in hyperglycemia. After a resting period 

 the blood-sugar rises again in some cases, in which as a result of the 

 stimulation it is lower than normal. 



In discussing the nature of pancreatic diabetes Knowlton and Star- 

 ling say that it has been suggested that the normal function of the pan- 

 creas is to diminish excessive production of sugar, and that in the absence 

 of its restraining influence excessive production and mobilization result. 

 On the other hand the fact that carbohydrates are not utilized by the body 

 when administered to animals in this condition has been interpreted as 

 showing that the tissues have lost their normal power of assimilating and 

 utilizing glucose. A third suggestion, though without much experimental 

 support, is that the sugar of the blood must be built up into some other 

 form before it can be used. Their own experiments would seem to show 

 that the pancreas normally produces a hormone which circulates in the 

 blood, and the presence of which is necessary to the assimilation and 

 utilization of the sugar of the blood by the tissue cells. 



McCoy follows Allen in his conception of the nature of diabetes as 

 due to a failure of the internal secretion of the pancreas, or as more ex- 

 plicitly expressed by Pavy, that there is a shortage or deficiency in the 

 number or quality of the sugar-amboceptors by means of which the dex- 

 trose of the blood is made available for oxidation in the tissues. 



Ervine's experiments showed that a depancreatized animal after the 

 development of the hyperglycemia and glycosuria still consumes glucose 

 at the same rate as the normal animal. He concludes that the hypergly- 

 cemia and glycosuria are dependent upon the rate of synthesis of glucose 

 into glycogen and not upon an interference with the normal rate of oxida- 

 tion. He believes, therefore, that the internal secretion of the pancreas 

 is an enzyme similar to that of the external secretion, but diverted into the 

 portal blood for the rapid synthesis of glucose into glycogen. Failure of 

 this action results in diabetes. The diabetic is one who fails to synthesize 

 the absorbed glucose into glycogen rapidly enough to prevent hyper- 



