FORMA TION OF GL YCO GEN. 9 1 9 



of starved rabbits two to four hours after a meal containing carbohydrates, and 

 disappears after five to eight hours' hard muscular work (dog). It is formed 

 in the muscles of a frog which has been deprived of its liver; 1 and may be 

 increased in muscular tissue by perfusing blood, to which grape-sugar has been 

 added, through the vessels of the muscle. 2 



The formation of glycogen from other than carbohydrate material. 

 That glycogen can be formed in the entire absence of carbohydrate 

 material from the food, is shown by the fact that animals which have 

 been for a long time fed on lean meat, deprived as much as possible of 

 carbohydrate, are found to have even considerable amounts of glycogen 

 in their liver and muscles. Indeed, if an animal be allowed to fast 

 for some days, and to perform also severe muscular work, circum- 

 stances under which practically the whole of the glycogen can be made 

 to disappear both from the liver and muscles, on now administering 

 proteid 3 or gelatin 4 food, altogether free from carbohydrates, glycogen 

 will reappear both in the liver and in the muscles. Even without the 

 administration of food, by the employment of narcotic drugs, such as 

 chloral, which tend to diminish or arrest muscular activity, glycogen 

 will reappear ; 5 in this case it must be formed from the proteids of the 

 body. The administration of fat without proteid does not cause such 

 reappearance, nor does the addition of fat to the food, even in consider- 

 able excess, increase the amount of glycogen in the liver. 6 Arsenic 

 poisoning causes a diminution in the glycogen both of the liver and of 

 the muscles; probably by impairing the vitality of their bioplasm. On the 

 other hand, the administration of glycerin promotes the storage of gly- 

 cogen in the liver ; 7 it acts, however, apparently rather by preventing the 

 removal of the glycogen, than by becoming itself converted into that 

 substance, or than by its becoming itself oxidized and thus acting as a 

 glycogen sparer (Eansom). Thus it is found that with glycerin adminis- 

 tration the sugar puncture is not able to produce glycosuria. 



The administration of ammonium carbonate was also found by Eohmann 8 

 to promote the accumulation of glycogen in the liver, and this property is 

 shared by many ammonium compounds, 9 but how they may act has not as yet 



3 Kiilz, Arch. f. d. yes. Physiol., Bonn, 1881, Bd. xxiv. S. 64. This volume contains 

 several other papers by Kiilz on the conditions of formation of glycogen. 



2 Kiilz, Ztschr. f. Biol., Miinchen, 1891, Bd. xxvii. S. 237: there was, however, 

 only an increase in three out of eleven experiments. 



3 ISTaunyn, Arch. f. expcr. Path. u. Pharmakol., Leipzig, 1875, Bd. iii. S. 94 ; v. 

 Mering, Arch. f. d. ges. Physiol., Bonn, 1876, Bd. xiv. S. 281 ; Kiilz, Funfzigj. Loct.- 

 Jubelf. d. . . . Carl Ludwig, Marburg, 1890. 



4 Salomon, Virchow's Archiv, 1874, Bd. Ixi. S. 352 ; Luchsinger, Inaug. Diss., Zurich, 

 1875 ; v. Mering, loc. cit. 



5 Zuntz u. Vogelius (Arch. f. Physiol, Leipzig, 1893, S. 378, Verhandl. d. physiol. 

 Gesellsch. zu Berlin] obtained a reappearance of glycogen on administering chloral to 

 starved and strychnised rabbits. 



6 Chauveau has come to the conclusion that carbohydrate may be formed from fat in 

 the animal body (Compt. rend. Acacl. d. sc., Paris, 1887, tome cxxii. p. 1098), and Seegen, 

 "Die Zuckerbildung," also holds this view, but the evidence in its favour appears to be very 

 insufficient. 



7 Weiss, Sitzungsb. d. k. Akad. d. Wisscnsch., Wien, 1873, Bd. Ixvii. S. 13 ; Eckhard, 

 loc. cit. ; Luchsinger, Inaug. Diss., Zurich, 1875 ; W. Ransom, Journ. Physiol., Cambridge 

 and London, 1887, vol. viii. p. 99 ; Schenck, Arch. f. d. gcs. Physiol., Bonn, 1894, Bd. 

 Ivii. S. 569. 



8 Arch. f. d. ges. Physiol., Bonn, 1886, Bd. xxxix. S. 21. Of. also Kiilz (Funfzigj. 

 Doct.-Jubelf. d. . . . Carl Ludwig, Marburg, 1890), who found that urea as well as 

 ammonia salts increased the glycogen of the liver. 



9 Nebelthau, Ztschr. f. BioL, Miinchen, 1892, Bd. xxviii. S. 138. 



