FATE OF GLYCOGEN IN THE ORGANISM 339 



place, for, after drawn blood has stood for about an hour in 

 the incubator, there is only a small reduction in its sugar 

 contents, a glycolysis far too feeble to account for the rapid 

 and extensive sugar destruction which undoubtedly occurs in 

 the body. The same is true for blood kept in a doubly 

 ligatured blood-vessel (living test-tube) ; its percentage of sugar 

 remains constant. 



Having obtained some evidence that it is in the muscles that 

 the dextrose is used up for on examining the blood coming 

 from a muscle in situ, especially an active one, there is, 

 according to most authorities, distinctly less dextrose than in 

 the arterial blood going to it we would expect an extract of 

 muscle, or its expressed tissue juice, to possess a distinct glyco- 

 lytic power, which, however, is not the case. 



As we shall see later, when the pancreas is completely excised, 

 dextrose ceases to be oxidised in the organism, so that it accumu- 

 lates in the blood and overflows into the urine, diabetes being 

 the result. This would lead us to expect that the pancreas must 

 normally furnish something to the organism which can produce 

 glycolysis. When, however, we try to demonstrate the presence 

 of this substance in pancreatic extract, or in the expressed juice 

 of the pancreas, it is impossible to obtain any positive result. 

 In all these cases a slight decomposition of dextrose may ensue, 

 which, if not the result of bacterial growth, is probably due 

 to the action of the oxidase or oxidising ferments universally 

 present in such extracts. 



A satisfactory explanation of these seemingly contradictory 

 results has recently been furnished by Cohnheim( 15 ), who has 

 found that if the expressed tissue juice of a muscle be mixed 

 with the expressed tissue juice of the pancreas, a mixture is 

 obtained which has great glycolytic power. Evidently, then, 

 muscle produces a ferment, itself incapable of decomposing dex- 

 trose, but which, when acted upon by an internal ferment derived 

 from the pancreas, becomes activated so that it quickly decom- 

 poses the dextrose. 



This mechanism is analogous with that which under certain 

 conditions exists in the intestine in connection with the action of 

 the proteolytic ferments of the pancreatic juice ; until this secretion 

 reaches the intestine it cannot digest proteid it contains only the 

 precursor of trypsin, viz. trypsinogen but when it mixes with 



