CARBOHYDRATES. 



47 



Chilodon, Amoeba, Rhizopoda) and also in fungi. 1 Clautrian, 2 as well as 

 Harden and Young, 3 has carefully determined and studied the amount of 

 glycogen in yeast. 



The identification of the glycogen has in many cases not been perfect, 

 and it is an open question as to whether some of the supposed glycogen has 

 not been an entirely different substance. At all events, these substances 

 belong, according to their biological relations, to the glycogen or starch 

 group, or, as we may say, to the group of reserve-carbohydrates. 4 



In the vertebrates the muscles also serve to store glycogen. The various 

 muscles contain different amounts, as shown by the following table: 5 



It is found not only in striated but also in smooth muscle and in the 

 muscle fibrils. The glycogen content in the muscles is dependent upon 

 the condition of nourishment. We shall soon see that the glycogen of 

 muscles has a particular function, and stands in direct relation to the 

 performance of work by the musculature. Even in invertebrates, glycogen 

 is not lacking in the muscular apparatus, and performs the same function. 



Glycogen occurs furthermore, in the pancreas, in the small glands of 

 the digestive apparatus, the lungs, kidneys, sexual glands, brain, epithe- 

 lium, connective-tissue, and blood- 8 and lymph vessels. 



B. Schondorff 7 has determined the amount of glycogen in different 



1 Errera: "Das Epiplasma der Ascomyceten und das Glykogen der Pflanzen," Briissel 

 (1882), and Compt. rend. 101, 253 (1885). 



2 Clautrian: "Chemische Untersuchungen iiber Glykogen," Mem. couronn. Acad. 

 Roy. Belg. p. 53 (1895). 



s Trans. Chem. Soc. 81 (1902). 



* Concerning the occurrence of glycogen under pathological conditions, see O. 

 Lubarsch in O. Lubarsch und R. Ostertag: Ergebnisse, 1, Jahr. 2, 166 (1895). 



5 August Cramer: Z. Biol. 24, 78 (1888). 



8 It is a much disputed question whether blood-plasma itself contains glycogen, or 

 whether the glycogen in blood is to be traced merely to that of the white blood-corpuscles. 

 It looks as if glycogen might be present in the plasma, though ordinarily its presence 

 is limited to the leucocytes. 



7 Pfliiger's Arch. 99, 191 (1903). 



