SECRETION. 453 



attendant symptoms may be much diminished by allowing a portion of the 

 gland to remain in situ, even though its capacity for the production of pan- 

 creatic juice is entirely abolished. Transplantation of the pancreas to the 

 subcutaneous tissue or to the abdominal cavity will practically prevent the 

 glycosuria. The explanations which have been offered as to the manner in 

 which the pancreatic tissue prevents and its absence gives rise to the excre- 

 tion of sugar are purely hypothetical. It has been claimed by some in- 

 vestigators that the pancreas secretes a specific material, which after its en- 

 trance into the blood and its distribution to the tissues, particulary the muscles, 

 promotes oxidation of the sugar. In the absence of this material the 

 oxidizing power is lost and hence the sugar accumulates, and is finally 

 eliminated by the kidneys. Since the discovery of the islands of Langer- 

 hans it has been suggested by some investigators that the production of the 

 material which regulates carbohydrate metabolism should be attributed to 

 them rather than to the pancreas as a whole. The presence however of a 

 glycolytic enzyme in either the pancreas or the muscle has not been positively 

 demonstrated, but if sugar be subjected to the action of a mixture of pancre- 

 atic and muscle juices, it is quickly oxidized, from which it has been inferred 

 that the secretion of the pancreas activates the enzyme of the muscle. That 

 the pancreas is actively associated with carbohydrate metabolism is indica- 

 ted by the fact that in a considerable percentage of cases of diabetes lesions 

 of the pancreas, more or less extensive, have been found. The sugar excreted 

 doubtless in part comes from the glycogen of the liver, as this disappears in a 

 short time. But as sugar continues to be excreted, even though all carbohy- 

 drates be withdrawn from the food, the conclusion is justifiable that it 

 arises in consequence of increased protein metabolism. This supposition is 

 strengthened by the fact that the quantity of urea excreted rises and falls with 

 the quantity of sugar excreted. 



Phlorizin, a glucoside obtained from the root bark of the cherry and 

 plum tree, gives rise to the appearance of sugar in the urine, in amounts 

 beyond that which might come from the glucose normally present in the 

 blood or from the glycogen of the liver. As there is a concomitant increase 

 in the amount of urea excreted, the supposition is that phloridzin increases 

 protein metabolism. 



Curara, in doses sufficient to paralyze the muscles, also gives rise to the 

 appearance of sugar in the urine. This is not due, however, to an increased 

 production on the part of the liver, but rather to a want of consumption on 

 the part of the muscles, due to their inactivity. The accumulation of the 

 sugar in the blood which takes place for this reason leads very promptly to 

 its removal by the kidneys. 



The Formation of Urea. It is now generally believed that the liver 

 is the most active of all the organs which may be engaged in the production 

 of urea. This belief is based on numerous physiologic and pathologic 

 data. The compounds out of which the hepatic cells construct urea have 

 been for chemic reasons asserted to be the ammonium salts, e.g., the car- 

 bonate, carbamate, and lactate, which are constantly present in the blood. 

 These salts, which result from protein metabolism, may be absorbed from 

 the tissues or from the intestines, carried to the liver, and there synthesized to 

 urea. This supposition is supported by an experiment as follows: The 



