CARBOHYDRATES. 73 



lost much of their significance since it has become known that the blood- 

 serum contains a ferment which is capable of converting glycogen and 

 starch into dextrose. 1 The fact that the muscles are capable of forming 

 glycogen from glucose has been proved by Kiilz. 2 By subcutaneous 

 injection of sugar into frogs with extirpated livers he was able to establish 

 the fact that there was an increase of muscle-glycogen. 



That the sugar content of the blood is directly dependent upon the liver 

 is shown by the fact that ablation of the liver causes the amount of sugar 

 in the blood to diminish and finally disappear. 3 



Although we have outlined the way carbohydrates break down in the 

 alimentary canal, the absorption of their hydrolytic products and their 

 destiny in the animal organism from the time of their being stored up as 

 glycogen on to their change back into d-glucose, still we have failed to give 

 an exact picture of the manner in which the glucose formed is eventually 

 consumed. We are, indeed, acquainted with the end-products, carbon 

 dioxide and water, and know that an oxidation takes place, but we are still 

 in doubt concerning the intermediate products. The destruction of the 

 sugar has been traced by Lepine 4 and others to the action of a glucolytic 

 ferment in the blood and in the tissues. Claude Bernard 5 had previously 

 shown that the sugar content of blood gradually diminishes on standing. 

 More recently it has been found that ferments of similar action are present 

 in almost all of the organs. It is hard to decide whether in all cases there 

 is no cooperation of micro-organisms, and as to what part this decom- 

 position of d-glucose plays in the living tissue. At all events, there is at 

 present no justification for the assumption that all of the sugar decomposi- 

 tion is caused by the action of the ferment mentioned. In this connection 

 we will refer to the work of Stoklasa. 6 He obtained from the expressed 

 juices of all sorts of different organs (muscles, liver, lungs, pancreas) by 

 precipitation with alcohol-ether, ferments which produced alcoholic fermen- 

 tation in a sterilized sugar solution without the aid of bacteria. The 

 proportion of carbon dioxide and alcohol formed was the same as in the 

 fermentation brought about by the zymase in yeast. The decomposition 



1 M. Bial: Pfliiger's Arch. 62, 137 (1892), and 64,73 (1893). Cf. also Rohmann, 

 Ber. 25, 3654 (1892). 



2 Pfliiger's Arch. 24, 64 (1881). 



3 Cf. Tangl and Harley: Pfliiger's Arch. 61, 551 (1895). Pavy and Siau: J. Physiol. 

 29, 375 (1903). Minkowski: Arch. exp. Path. Pharm. 21, 41 (1886). Schenk: Pfliiger's 

 Arch. 57, 553 (1894). 



* Compt. rend. 110, 742 (1890); 110, 1314; 112, 146 (1891); 112, 411; 112, 604; 112, 

 1185 and 1414; 113, 118 (1891); 120, 139 (1895). Lupine: Le ferment glycolytique et la 

 pathog&iie du diabete, Paris, 1891 . Cf . Nasse and Framm : Pfliiger's Arch. 63, 203 (1896) . 



5 Legons sur le diabete (1878). 



8 Hofmeister's Beitr. 3, 460 (1903); Ber. 36, 4058 (1903); Pfliiger's Archiv. 101, 311 

 (1904); Zentr. Physiol. 17, 465 (1903); and Ber. 38, 664 (1905). 



