318 HANDBOOK OF PHYSIOLOGY. 



Internal Secretion of the Pancreas. 



Minkowski and von Mering have shown that total extirpation of the 

 pancreas is followed in all cases in the course of a few hours by the ap- 

 pearance of sugar in the urine. The amount of sugar which appears is 

 considerable from 5-10 per cent. This experimental disease (diabetes 

 mellitus) is accompanied by an increase in the quantity of urine and by 

 abnormal thirst and appetite, and proves fatal in 15 days or less. These 

 results are obtained only when the entire gland or more than nine-tenths 

 of it have been removed. If one-tenth of the gland be left behind, 

 sugar appears in the urine when carbohydrates are eaten, but not other- 

 wise. Nor is it necessary that the remaining portion of the gland be in 

 its normal situation. Successful grafts under the skin of the abdomen 

 or elsewhere will prevent the appearance of sugar in the urine and the 

 other symptoms. If, however, the graft be subsequently removed, the 

 sugar in the urine and the other symptoms reappear, and the experi- 

 mental disease proceeds to a rapidly fatal issue. 



The symptoms produced by total extirpation of the pancreas do not 

 depend upon the loss of the pancreatic juice proper to the organism. 

 This secretion may be diverted from the intestine through a pancreatic 

 fistula without the production of diabetes. Moreover, Hedon and Thiro- 

 loix have rendered the acini of the gland functionally inactive, and ul- 

 timately destroyed them, by the injection of paraffin or other substances 

 into the duct of Wirsung, without the supervention of diabetes. These 

 experiments have led to the conviction that the little groups of epithelial- 

 like cells situated in the connective-tissue stroma of the pancreas secrete 

 something which is absorbed into the circulation and constitutes its 

 internal secretion. Lepine and Boulud have recently extracted from the 

 urine of patients suffering from diabetes or pneumonia a crystalline sub- 

 stance which produces glycosuria when injected under the skin or into 

 the jugular vein of animals. This substance loses its power if passed in 

 the blood through the vessels of a living pancreas. They conclude, 

 therefore, that the pancreas, possibly through its internal secretion, has 

 an antitoxic function and favors glycolysis in the tissues by destroying 

 the substance which inhibits the conversion of glucose into glycogen or 

 fat. 



Internal Secretion of the Liver. 



This subject will be considered at length when we come to study the 

 formation of glycogen (see p. 435). 



The Spleen is the largest of these so-called vascular glands; it is 

 situated to the left of the stomach, between it and the diaphragm. It 



