QUANTITY OF HEPATIC GLYCOGEN. 747 



modified form, in the hepatic cells or elsewhere. More sugar, certainly, 

 is obtainable from the livers of Herbivorous than from those of Car- 

 nivorous animals, and m$>re from Herbivorous animals recently fed on 

 amylaceous food ; but glycogen continues to be formed in^the livers of 

 fasting or actually starved animals, and of animals fed for a month or 

 more exclusively on flegh. in s"uch instances, the glycogenic sub- 

 stance found in the liver cannot be derived directly from food, but is 

 formed by some action of the hepatic cells 7 in which, as already men- 

 tioned, minute grains, apparently of an amyloid nature, have been 



The constituents of the flesh used as lood, which can be 

 thus metamorphosed by the hepatic cells, are fat and albuminoid 

 substances ; for the small quantities of amyloid matter sometimes 

 found in flesh, and of inosite or muscle-sugar always present in it, 

 which is incapable of the alcoholic fermentation, and does not turn the 

 rays of polarized light, are not sufficient to produce it. By some, it 

 has been supposed that the hepatic cells have the power of decom- 

 posing the neutral fats of the food into glycerin and the fatty acids, 

 stearic and oleic ; furthermore, that the former is the source of the 

 glycogen, and that the latter assist in the formation of the fatty acids 

 of the bile : thus, 2 of glycerin, i. e., 2 (C 3 H 8 3 ) -f 2 of oxygen (0 2 ), 

 are equal to 1 of glycogen (C 6 H 10 5 ) -f- 3 of water 3 (H 2 0). It has 

 been objected to this, that the formation of sugar and of bile in the 

 snail, has been observed to be an alternately performed function. (Ber- 

 nard.) Another mode of origin of the glycogen from fatty matter 

 supposes that the conjugated fatty acids of the bile, taurocholic and 

 glycocholic acids, are first formed, that they are then reabsorbed from 

 the intestinal canal by the portal vein, and are decomposed into gly- 

 cogen and a nitrogenous product, which is ultimately converted into 

 urea, and eliminated by the kidneys ; for dogs with biliary fistulas 

 appear to have no glycogen in the liver, and other dogs, after long 

 fasting, if fed with taurin, show an abundance of glycogen in that 

 organ. By some, again, albuminoid principles are supposed to be 

 decomposed in the hepatic cells ; according to one view, the products 

 are glycogen and the two conjugated biliary acids, one of which con- 

 tains nitrogen, and the other, in addition, sulphur ; according to 

 another view, they are glycogen, and various nitrogenous bodies, such 

 as creatin, creatinin, and other substances, which are ultimately 

 excreted as urea. The continuous formation of sugar in the eggs of 

 birds, during incubation, shows that glycogen may be formed inde- 

 pendently of amylaceous food, and its origin from albuminoid matter 

 is rendered probable, from the fact that in animals fed on fat or ole- 

 aginous food alone, or even on pure starch, as distinguished from vege- 

 table food containing starch mixed with other constituents, the gly- 

 cogen is much diminished in quantity (Stokvis) ; whereas, in those fed 

 on gelatin it is almost normal in quantity, and attains its maximum 

 in animals fed on highly albuminous diet. (Bernard and Schmidt.) The 

 experiments of Dr. Pavy alone give opposite results, showing the 

 greatest amount of sugar in animals fed on vegetable food only ; but 

 the increase of sugar then observed by him might be partly owing to 

 sugar formed from the food itself. He found, in the livers of dogs, 



