322 THE METABOLISM OF THE CARBOHYDRATES 



(sarcoplasm) ; but in poorly fed animals it can be detected only 

 in the interfibrillary material. In festal life, it appears in the 

 muscles as soon as their histological structure in differentiated. 

 During starvation, the glycogen in the muscles remains for some 

 time after all of it in the liver has disappeared. 



The amount of glycogen varies considerably in the different 

 muscles of the same individual, as the following table of observa- 

 tions on three dogs shows : l 



TABLE I 



The percentage of glycogen in the muscles of the dog has 

 been found to rise, under certain conditions, to 3 '72 per cent. 

 (Schondorff 7 ). 



For an estimation of the total amount of glycogen in the 

 muscles of an animal, it is therefore not allowable to determine 

 the percentage in a small piece of any muscle and calculate from 

 this the amount in all the muscles ; even by multiplying by two 

 the amount of glycogen found in one -half of the body, only an 

 approximate result of the total amount in the body is obtained, 

 since, as A. Cramer has shown, corresponding muscles on the 

 opposite halves of the body do not contain the same amount of 

 this substance. A difference of 27 '7 per cent, was found in one 

 investigation in which the glycogen content of the two hind 

 limbs was compared. Heart muscle contains more glycogen 

 than skeletal muscle. 



In none of the other tissues or organs is the percentage of 

 glycogen so high as in the liver and muscles, but traces at least 

 of it are to be found almost everywhere in the body. Even in 

 such tissues as cartilage and bone has glycogen been found ; in 

 the blood it is found in the leucocytes, but there is none in the 

 plasma ; it is present in the epithelial cells lining the gastro- 



Cramer. Briicke-Kiilz method ( 6 ). 



