FOOD AND DIGESTION 67 



detected in increased amounts in the liver. The volun- 

 tary muscles also possess the same "glycogenic" func- 

 tion, and glycogen is deposited in them also. If exces- 

 sive amounts of a readily absorbable sugar is fed, the 

 amount entering the portal circulation is too great for 

 the liver and muscles to handle, and some of the dex- 

 trose appears in the urine. This condition is known as 

 "alimentary glycosuria" to distinguish it from the 

 forms of glycosuria due to disease. When need arises 

 the glycogen is reconverted into dextrose and is used to 

 yield energy to contracting muscles or secreting glands 

 or to other functioning tissues. This energy-yielding 

 process is strongly suggestive of a similar yield of en- 

 ergy when fuel containing carbon and hydrogen is 

 burned outside the body, and the end results of the 

 combustion of carbohydrate either in the body or out- 

 side are the same, namely, water and the gas, carbon 

 dioxide. Occasionally, we see persons whose tissues 

 can not utilize the dextrose furnished them, and here, 

 as in the alimentary glycosuria, the amount of dextrose 

 in the blood increases beyond the amount that the kid- 

 neys can hold back and sugar appears in the urine. 

 This condition constitutes "diabetes mellitus." The 

 wasting away that usually accompanies severe cases 

 illustrates the importance of the carbohydrates in the 

 diet. 



When larger amounts of carbohydrates are fed, 

 amounts larger than are needed for the energy require- 

 ments, much of it may be converted into fat and stored. 

 The well-known effects of excessive candy eating are 

 explainable on this basis. To a verj^ small extent, carbo- 

 hydrate may be used to help build up the tissues of the 

 body, but this occurs in such a limited way as to be 

 negligible. 



