4IO TEXT-BOOK OF PHYSIOLOGY. 



aceto-acetic and oxybutyric acids make their appearance, attended 

 by the usual symptoms characteristic of glycosuria in man. The 

 quantity of sugar excreted and the gravity of the 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 pancreatic 

 juice is entirely abolished. Transplantation of the pancreas to the 

 subcutaneous tissue or to the abdominal cavity will practically pre- 

 vent 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 excretion of sugar are purely hypothetical. It has 

 been claimed by some investigators that the pancreas secretes a 

 specific material, which enters the blood and promotes oxidation of 

 the sugar. In the absence of this material the sugar accumulates, 

 and is finally eliminated by the kidneys. Since the discovery of the 

 islands of Langerhans it has been suggested by some investigators that 

 the production of the material which regulates carbohydrate metabo- 

 lism should be attributed to them rather than to the pancreas as a 

 whole. The sugar excreted doubtless in part comes from the glycogen 

 of the liver, as this disappears in a short time. But as sugar con- 

 tinues to be excreted, even though all carbohydrates be withdrawn 

 from the 'food, the conclusion is justifiable that it arises in conse- 

 quence of increased proteid metabolism. This supposition is 

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

 falls with the quantity of sugar excreted. 



Phloridzin, a glucoside obtained from the leaves of the cherry and 

 plum tree, gives rise to the appearance of sugar inj;he 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 proteid 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 inac- 

 tivity. The accumulation of the sugar in the blood which takes place 

 for this reason leads very promptly to its removal by the kidneys. 

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

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

 V rod ^lHLf ureal TRTTtJeTieTIs 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 carbonate^ lactate, carbamate, which are 

 constantly present in the blood. These salts, which result from 

 proteid metabolism, are absorbed from the tissues, carried to the 

 liver, and there synthesized to urea. This supposition is supported 



