GLYCOGEN AND ITS FORMATION. 



347 



drugs. As will be seen later on, the increased excretion due 

 to drugs always coincides with suprarenal overactivity, hence 

 with enhanced oxidation. It thus becomes apparent that many 

 constituents of the urine, normal and abnormal, the origin of 

 which is obscure, are due to variations in the oxidation processes 

 in the intercellular capillaries of the liver, caused by corresponding 

 fluctuations in the functional activity of the adrenals. 



Glycogen and its Formation. Glycogen obviously removes 

 our inquiry from the arteriole to the hepatic cell, since this 

 organ is that in which it accumulates; but we must not lose 

 sight of the important fact that two processes are involved in 

 the analysis, (1) the formation of the glycogen and (2) its con- 

 version into dextrose, and that the latter reactions must 

 occur in the vascular channels. Again, the first process seems 

 so bound up with the formation of the bile that it becomes 

 necessary to consider this subject simultaneously to avoid repe- 

 tition. 



The sponge-like construction of the hepatic cell due to its 

 vacuoles, the delicate canals described by J. W. and E. H. 

 Fraser, Browicz, and Schafer, and finally, the bile-collecting 

 vacuole, or vesicle, leading through its own canaliculi to the 

 perilobular bile-capillaries, does not appear to afford much 

 room for protoplasm capable of undergoing functional metabo- 

 lism, since this would have to be embodied in the partitions 

 separating all these cavities. Yet, were it otherwise, the 

 nucleus often duplicated, particularly in herbivorous animals, 

 almost one-third in size that of the entire cell, and containing 

 nucleoli would represent a useless structure. It seems evi- 

 dent, judging by the appearance of the cell as a whole, there- 

 fore, that the nucleus, which, as we have seen, is surrounded 

 by a thin limiting layer of protoplasm, must impart its energy 

 to this layer. This, in turn, being the central terminal of all 

 the partitions, which, along with the cell's own pseudocovering, 

 are protoplasmic, the vacuoles become receptacles, as it were, 

 of the products of their walls. 



Again, when we behold the minute canals so clearly shown 

 in Schafer's illustration (shown on page 340) a direct commu- 

 nication with parts external to the cell is evident in several 

 places, and it seems clear that, if his carmine gelatin could 



