324 THE METABOLISM OF THE CARBOHYDRATES 



HOW THE TISSUES MAY BE RENDERED FREE OF GLYCOGEN 



By starvation alone it is impossible to render the liver glycogen- 

 free or the blood free of sugar. Moreover, if several animals of the 

 same kind be starved for the same length of time, the amount of 

 glycogen which remains in their tissues will be found to vary con- 

 siderably ; for example, in seven hens starved for six days the total 

 amount of glycogen in the body at the end of starvation was found 

 by Edward Ktilz ( 6 ) to be: 0-7010 grm. ; 0-5433 grm. ; 0*0425 

 grm.; 0-3332 grm.; 1-3939 grm.; 1-0788 grm.; 1-7607 grm. 

 Pfliiger also records a dog which was starved for twenty-eight 

 days, and the liver of which contained at the end of this period 

 22" 5 grm. glycogen. V. Mering ( 6 ) states that in one dog after 

 eighteen days, and in another after twenty-one days of complete 

 starvation, 0*48 grm. glycogen was obtained from the liver. 

 Indeed, as starvation proceeds, the amount of glycogen may, 

 after attaining a minimum, increase slightly in amount, as, for 

 example, when all the available fat has been used up and the 

 tissue proteids begin to break down, as occurs in starvation a 

 few days before the death of the animal. 



In several animals of the same kind, therefore, starved for 

 the same length of time and to all outward appearance identical, 

 the amount of glycogen may be very variable, and the same is 

 true when the animals are fed with exactly the same amount 

 and kind of food ; thus, the glycogen deposited in the tissues 

 of similarly fed dogs may vary from 7' 59 grm. to 37*87 grm. per 

 kg. body weight (Schondorff). On this account, great care must 

 be taken in drawing conclusions from the amount of glycogen 

 found in the body after death regarding the power of any food- 

 stuff in influencing glycogen formation. 



Starvation alone cannot be depended on to entirely deprive the 

 tissues of their glycogen. If, however, it be combined with certain 

 other agencies, which also tend to cause the disappearance of 

 glycogen in the body, much more satisfactory results can be 

 obtained. The most important of these agencies is muscular work. 

 This causes the liver glycogen to disappear in a few hours, although 

 it takes longer to make the muscles glycogen-free. A method for 

 clearing the organism of glycogen, which includes starvation and 

 muscular work, is that described by Bendix ( 8 ), in which dogs 



