144 NUTRITIONAL PHYSIOLOGY 



may be said that the glycogen is like a checking account 

 which a man uses to pay his routine expenses, drawing 

 upon it often and recruiting it at longer intervals. Such 

 an account is sometimes nearly wiped out and then at one 

 stroke largely increased. The fat of the body is like a 

 savings bank deposit, gathered slowly, drawn upon only 

 in emergencies, and, it may be added, gaining by com- 

 pound interest in many cases. 



Two facts readily suggest themselves which may be 

 used to explain the low limit of glycogen storage. For 

 one thing, its physical properties would probably make a 

 high percentage of it undesirable. In the second place, 

 there is a distinct economy in substituting fat for glycogen 

 because fat represents more energy in proportion to its 

 mass. An individual who carries 20 pounds of adipose 

 tissue may wish to be rid of a part of it, but if he were com- 

 pelled to bear a load of glycogen equivalent in energy his 

 burden would amount to about 45 pounds. 



The Pancreas and Carbohydrate Metabolism. We 

 have repeatedly compared the carbohydrate of the body 

 to money. Just as it is the eventual function of money to 

 be spent, so it is the destiny of carbohydrate to be oxidized 

 that its latent energy may be turned to account. This 

 oxidation takes place chiefly in the muscles, to some extent, 

 doubtless, in the glands, the gray matter of the nervous 

 system, and the absorbing cells of the intestine. The in- 

 tensity of the local process will in every case be proportional 

 to the heat and other forms of energy developed. Consid- 

 ering the wide distribution of this purposeful destruction 

 of sugar it is surprising to find it all dependent upon an 

 obscure action of the pancreas. 



This organ has been dwelt upon previously as a most im- 

 portant contributor of digestive juice to the intestine. It 

 would be anticipated that the removal of the pancreas 

 from an animal would be followed by defects of digestion 

 and assimilation. This is probably justified by the results 

 of a trial, but the effect upon digestion is overshadowed by 

 a consequence hardly to be foreseen. This is the almost 



