350 THE ADRENAL, GENERAL MOTOR, AND VAGAL SYSTEMS. 



artery to each lobule, to properly regulate the functions in- 

 volved, only the required sugar is burnt by the oxidizing sub- 

 stance. The rest, under the influence of the nuclei of the 

 hepatic cells and the mural protoplasm of the latter, is con- 

 verted into glycogen and collected in the adjoining alveoli. 



But we must also account for the elimination of the many 

 waste-products that are found in bile. An interesting feature 

 connected with these fatty acids is that they can combine 

 synthetically with other bodies, even with proteids, while they 

 are simultaneously able to emulsify the more insoluble soaps 

 and other fatty acids and thus insure their elimination. Again, 

 cholesterin, mainly derived from the white matter of the 

 cerebro-spinal axis and nerves (Flint), in which it occurs in 

 abundance (Foster), was formerly considered as a fatty sub- 

 stance capable of undergoing saponification, but it is now 

 classed among alcohols: the only alcohol that occurs in the 

 organism in a free state. This body is not only soluble in 

 solutions of the biliary acids also, but it combines with acids, 

 including glycocholic acid. The importance of this fact appears 

 when it is recalled that insufficiency of glycocholic acid in this 

 connection and also, perhaps, of oxidizing substance is the 

 main source of gall-stones. The cholesterin being a constant 

 constituent of bile, when there is not enough glycocholic acid 

 present to take it up, it is precipitated in the gall-bladder and 

 there forms the calculi of which it is the main component. 

 Another body derived from nervous structures, but which, like 

 cholesterin, is to be found in other fluids, especially blood- 

 serum, is lecithin. This body, besides others not mentioned, 

 only occurs, however, in very limited proportions. 



It is now evident that glycocholic acid and taurocholic 

 acid should be looked upon as functional acids, in the sense 

 that they are not only vehicles for waste-products of metabo- 

 lism, but are also capable of submitting them to dissociating 

 reactions under the influence of the oxidizing substance. They 

 are sources of energy precisely as myosinogen appears to be a 

 source of energy, and capable of becoming factors of combus- 

 tion phenomena when in contact with the latter substance. 

 They are also truly physiological in the sense that they serve 

 to recover or economize those products which can again be 



