FORMATION OF SUGAR IN THE LIVER, 335 



other means calculated to interfere with the action of a 

 ferment on the amyloid substance of the organ. Instead 

 of adopting Bernard's view, that normally, during life, 

 glycogen passes as sugar into the hepatic venous blood, and 

 thereby is conveyed to the lungs to be further disposed of, 

 Pavy inclines to believe that it may represent an interme- 

 diate stage in the formation of fat from materials absorbed 

 from the alimentary canal. 



For the present we must remain uncertain as to which 

 of these theories contains most truth in it. 



Whatever be the destination of this peculiar amyloid 

 substance formed at the liver, most recent observers agree 

 that it is formed at, and exists within, the hepatic cells, 

 from which it may be extracted by the process just de- 

 scribed. 



Much doubt exists also respecting the mode in which 

 glycogen is formed in the liver, and the materials 

 which furnish its source. Since its quantity is increased 

 after feeding, especially on substances containing much 

 sugar or starch, it is probable that part of it is derived 

 from saccharira principles absorbed from the digestive 

 canal ; but since its formation continues even when there 

 is no starch or sugar in the food, the albuminous or fatty 

 principles also have been thought capable of furnish- 

 ing part of it. Numerous experiments, however, having 

 proved that the liver continues to form sugar in animals 

 after prolonged starvation, and during hybernation, and 

 even after death, its production is clearly independent 

 of the elements of food. One of Bernard's experiments 

 may be quoted in proof of this : Having fed a healthy dog 

 for many days exclusively on flesh, he killed it, removed 

 the liver at once, and before the contained blood could 

 have coagulated, he thoroughly washed out its tissue by 

 passing a stream of cold water through the portal vein. 

 He continued the injection until the liver was completely 

 exsanguined, until the issuing water contained not a trace 



