354 THE ADRENAL, GENERAL MOTOR, AND VAGAL SYSTEMS. 



filtered off from the coagulated proteids. Xo sugar, or only 

 traces of it, is found in the extract, but another carbohydrate 

 glycogen, an isomer of starch, giving a port-wine color with 

 iodine and capable of ready conversion into sugar by amylolytic 

 ferments is present in large amount. Again, the liver, after 

 the death of the animal, is left for a time in situ, or, if excised, 

 is kept at a temperature of 30 to 40 C. or for a longer period 

 at a lower temperature; it is then treated exactly as before, 

 but no glycogen, or comparatively little, can now be obtained 

 from it, although sugar (dextrose) is abundant. The infer- 

 ence plainly is that after death the hepatic glycogen is con- 

 verted into dextrose by some influence which is restrained or 

 destroyed by boiling. This influence may be due to an un- 

 formed ferment or to the direct action of the liver-cells, for both 

 unformed ferments and living tissue-elements are destroyed 

 at the temperature of boiling water." 



Another explanation suggests itself to us if, instead of a 

 ferment of hepatic origin, we hypothetically use one of ex- 

 ternal origin: In the first procedure immediate immersion in 

 boiling water destroyed the ferment which happened to be in 

 the blood-vessels, while, in the second, the ferment was given 

 time to act. The difference in the conclusions vouchsafed is 

 simply this: no thought being given to the blood-vessels, the 

 ferment could only be considered as of cellular origin. We 

 have seen how many functions ascribed to the hepatic cells 

 really belonged to the intercellular blood-stream; this seems 

 to be an additional one. 



Admitting that we are dealing with a ferment of external 

 origin, from which organ could we expect it to be derived? 

 Can we attribute the process to ferments from the salivary 

 glands or pancreas? If it is produced only by digestive fer- 

 ments, i.e., amylolytic ferments poured out during digestion, 

 why does glycosuria appear irrespective of any digestive 

 process when the floor of the fourth ventricle is punctured, as 

 shown by Claude Bernard? He also found that conversion of 

 glycogen into sugar was a continuous process, carried on to 

 subserve the needs of the organism: a perfectly logical con- 

 clusion if the liver is really a storehouse for this substance. 

 Again, the quantity of sugar in the blood, as we have seen, 



