OH. xxxiii.] GLYCOGEN. 59 



food taken is also well shown by the following results, obtained 

 by the same experimenter : 



Average Quantity of Glycogen found in the Liver of Rabbits after 

 Fasting, and after a Diet of Starch and Sugar respectively. 



Average amount of Glycogen in Liver. 



After fasting for three days . . Practically absent. 

 diet of starch and grape-sugar . 15-4 per cent. 

 ,, cane-sugar . . . 16*9 ,, 



The diet most favourable to the production of a large amount 

 of glycogen is a mixed diet containing a large amount of carbo- 

 hydrate, but with some proteid. Fats taken in as food do not 

 increase the amount of glycogen in the cells. Glycerin injected 

 into the alimentary canal may increase the glycogen of the liver, 

 probably because it hinders the conversion of glycogen into sugar 

 and other substances; the glycogen therefore is allowed to 

 accumulate in the liver. 



Destination of Glycogen. There are two chief theories as to 

 the destination of hepatic glycogen. (i.) That the glycogen is 

 converted into sugar during life by the agency of a ferment (liver 

 diastase) also formed in the liver ; and that the sugar is conveyed 

 away by the blood of the hepatic veins, to undergo combustion in 

 the tissues. (2.) That the conversion into sugar only occurs 

 after death, and that during life no sugar exists in healthy livers, 

 glycogen not undergoing this transformation. 



The first view is that of Claude Bernard, and has been adopted 

 by the majority of physiologists. The second view is that of 

 Dr. Pavy : he denies that the liver is a sugar-forming organ, he 

 regards it as a sugar-destroying organ ; the sugar is stored as 

 animal starch, but never again leaves the liver as sugar during 

 life. He has been unable to find more sugar in the hepatic blood 

 than in the portal blood. Other observers have found an increase 

 in the sugar of the blood leaving the liver, but the estimation 

 of sugar in a fluid rich in proteids, as is the blood, is a matter 

 of great difficulty. Even if the increase is so small as hardly to 

 'be detected, it must be remembered that the whole blood of the 

 body passes through the liver about twice a minute, so that a 

 very small increase each time would mount up to a large total. 



Pavy further denies that the post-mortem formation of sugar 

 from glycogen that occurs in an excised liver is a true picture 

 of what occurs during life, but is due to a ferment which is only 

 formed after death. During life, he regards the glycogen as a 

 -source of other substances, like fat and proteid. It is certainly 



