GLYCOGEN. 369 



(Bizio), Tsenia and Ascaridae (WEiNLAND 1 ), are very rich in glycogen. 

 Glycogen also occurs in the vegetable kingdom, especially in many fungi. 



The quantity of glycogen in the liver, as also in the muscles, depends 

 essentially upon the food. In starvation it disappears almost com- 

 pletely after a short time, but more rapidly in small than in large animals, 

 and it disappears earlier from the liver than from the muscles. As 

 shown by C. VOIT, KULZ and especially by PrLUGER, 2 it never entirely 

 disappears in starvation, as a reformation of glycogen always takes 

 place. After partaking of food, especially such as is rich in carbo- 

 hydrates, the liver becomes rich again in glycogen, the greatest incre- 

 ment occurring 14 to 16 hours after eating (KULZ). The quantity of 

 liver-glycogen may amount to 120-160 p. m. after partaking of large 

 quantities of carbohydrates, and in dogs which had been especially 

 fed for glycogen SCHONDORFF and GATIN-GRUZEWSKA found still higher 

 results, even more than 180 p. m. Ordinarily it is considerably less, 

 namely, 12-30 to 40 p. m. The highest amount of glycogen in the liver 

 thus far observed was 201.6 p. m., found by MANGOLD 3 in the frog. The 

 shark, whose liver is very rich in fat, even though well nourished, only 

 has comparatively low values for the glycogen in the liver, 9.3-23.8 

 p. m. (BoTTAZzi 4 ) . According to GREMER the quantity of glycogen in 

 plants (yeast-cells) is, as in animals, dependent upon the food. He 

 finds that the yeast-cells contain glycogen, which disappears from 

 the cells in the auto-fermentation of the yeast, but reappears on the 

 introduction of the cells into a sugar solution. 



The quantity of glycogen of the liver (and also of the muscles) is 

 also dependent upon rest and activity, because during rest, as in hiberna- 

 tion, it increases, and during work it diminishes. KULZ has shown that 

 by hard work the quantity of glycogen in the liver (of dogs) is reduced 

 to a minimum in a few hours. The muscle-glycogen does not diminish 

 to the same extent as the liver-glycogen. KULZ, ZUNTZ and VOGELIUS, 

 FRENTZEL, and others have been able to render rabbits and frogs nearly 

 glycogen-free by suitable strychnine poisoning. The same result is pro- 

 duced by starvation followed by hard work. According to GATIN- 

 GRUZEWSKA, 5 the liver and muscles in rabbits can be made glycogen- 



1 Zeitschr. f. Biologie, 41. The extensive literature on glycogen may be found in 

 E. Pfliiger, Glykogen, 2. Aufl., Bonn, 1905; and in Cremer, " Physiol. des Glykogens," 

 in Ergebnisse der Physiologic, 1, Abt. 1. In the following pages we shall refer to these 

 works. 



2 Pfluger's Arch., 119, which contains the literature. 



3 Pfluger's Arch., 121. 



4 Arch. Ital. d. Biol., 48; cited in Bioch. Centralbl., 7, 833. 



5 Compt. rend., 142. 



