STORAGE OF CARBOHYDRATES IN THE BODY 



125 



sides of the body do not have exactly the same percentages; hence it is not 

 sufficient to analyze single muscles in order to obtain the amount of glycogen 

 in the animal body. 



In the following table are brought together some data on the percentage of 

 glycogen in the new-born child, in a dog after a twenty-eight days' fast, and 

 in the frog: 



The total quantity of glycogen calculated as sugar in Pfliiger's fasting dog was 

 52.5 g. i. e., 1.5 g. per kilogram of body weight. 



The amount of glycogen in the body is raised considerably by rich feeding. 

 In a fattened goose, as much as 22.2 g. per kilogram of body weight has- 

 been observed. 



From many analyses of the organs of hens and rabbits, Otto has found that 

 the absolute quantity of glycogen in the liver is about half the total quantity 

 in the body. The same appears from Pfliiger's experiment on the fasting- dog. 

 When therefore Pavy found in the dog's liver alone a quantity of glycogen 

 amounting to 7.82 g. per kilogram, it is to be supposed that the total quantity 

 in the animal's body was about 15 g. per kilogram. Pfliiger takes 11 g. as the 

 average amount of glycogen per kilogram in the dog. 



In man the glycogen in the liver is estimated at 150 g., and the total amount 

 in the body at 300 g., which is only about 4 g. per kilogram. Possibly this esti- 

 mate is too low. 



Glycogen is laid down in the cells of the liver in large flakes (Fig. 45). 

 It is deposited in the muscles partly between the fibrillae and partly in them. 



It is evident that glycogen must be formed in the liver because not only 

 does it occur there in largest quantities, but when animals previously deprived 

 of most of their glycogen by a fasting period are fed with carbohydrates, the 

 liver is the first of all the organs to show a storage of glycogen. An inde- 

 pendent formation of glycogen in other organs, and especially in muscles, is 

 not thereby excluded, however, and in fact there are certain indications that 

 glycogen is thus formed. For example: glycogen has been demonstrated in 

 chick embryos before the rudiment of the liver appears, whereas the egg, be- 

 fore development, is said to contain no glycogen ; the glycogen of the muscles 

 of fowls presents certain differences from the liver glycogen ; again paralyzed 

 muscles are loaded wrth glycogen, etc. But this question probably ought not 

 to be regarded as definitely settled. 



