526 DIABETES 



if the animal is starved. Feeding of carbohydrates increases 

 it greatly, and the greater part of the sugar administered may 

 appear in the urine. Pancreatectomized dogs live at most two 

 to three weeks, death being due not so much to the disturbance 

 of metabolism as to infection of the operation wounds, which 

 heal poorly because of the high sugar content of the blood 

 (Pfluger). 



While the amount of glycogen in the liver and muscles 

 decreases greatly, the amount of sugar in the blood is increased. 

 Instead of the normal 1 part per thousand, as much as 7 to 10 

 parts of sugar may be present per thousand parts of blood, and 

 the glycosuria is, as in the case of nervous glycosuria, dependent 

 upon hyperglycemia and consequent elimination of the excessive 

 sugar by the kidneys. Since it has been proved that absence 

 of the pancreatic juice is not responsible for the glycosuria, the 

 only remaining explanation of this hyperglycemia is that it is 

 the result of the loss of some internal secretion, or the absence 

 of some direct action of the pancreas itself upon the blood 

 passing through it. The following explanations suggest them- 

 selves : 



(1) The pancreas may directly destroy sugar coming to it in 

 the blood. 



(2) It may secrete an enzyme that destroys sugar in the 

 blood. 



(3) It may neutralize or destroy some toxic substance that 

 interferes with sugar metabolism. 



(4) It may secrete some substance that is itself necessary for 

 proper sugar metabolism in the liver and other tissues of the 

 body. 



As to the first possibility, it can only be said that we have 

 no evidence whatever that the pancreas is the site of any con- 

 siderable active sugar destruction. Repeated investigations have 

 failed to show that the pancreas has any marked powers of 

 glycolysis, or contains any particularly active glycolytic enzyme 

 as compared with other organs. That the chief function of the 

 pancreas in carbohydrate metabolism consists of furnishing a 

 glycolytic enzyme to the blood has been completely disproved. 

 The blood does exhibit some glycolytic power, but this is far too 

 slight to account for the daily destruction of several hundred 

 grams of sugar, and, furthermore, there is every reason to 

 believe that this destruction takes place in the tissues, and not 

 in the blood. If the pancreas is removed, the glycolytic power 

 of the blood is not decreased, showing that it is not derived 

 from the pancreas, and the blood of the pancreatic vein is no 



