INGESTION OF CARBOHYDRATES. 249 



ticularly on the respiratory quotient, it is conceivable that with the 

 ingestion of sucrose or levulose the fat metabolism may not be com- 

 pletely suppressed and that we may have a very considerable formation 

 of fat from carbohydrate with a slight fat combustion still progressing. 

 The actual proof of this is, however, beyond the possibilities of existing 

 technique. 



The intermediary processes must be still further considered and the 

 fact recognized that when the body is surcharged with carbohydrate, 

 as it is after the ingestion of 100 grams of sugar, there may result a 

 considerable deposit of glycogen. This process would be without 

 action upon the respiratory quotient and one might suppose it to be 

 without action upon the total metabolism. It is nevertheless a fact 

 that in the experiments with an initial respiratory quotient so low as 

 to suggest a glycogen-poor reserve there was no evidence of a sufficient 

 storage in the body of the ingested carbohydrate to produce a marked 

 decrease in its effect upon the total metabolism. 



One of the most striking illustrations of this fact was in the experi- 

 ment with H. H. A. on January 2, 1912, in which 100 grams of sucrose 

 were given (see table 176). The store of glycogen in the body of this 

 subject was presumably very low, as evidenced by the basal respiratory 

 quotient of 0.72. This was due to the fact that a few days previous 

 he had been the subject of a series of experiments with a carbohydrate- 

 free diet. If this subject had first replenished his glycogen store 

 with carbohydrate before the ingested material was katabolized or 

 before any portion of it was converted to fat, we should not expect an 

 immediate increment of either the total metabolism or the respiratory 

 quotient. As a matter of fact, the ingestion of 100 grams of sucrose 

 in this particular case resulted in the maximum increment for the 

 entire series with sucrose in both the heat and carbon-dioxide produc- 

 tion and very nearly the maximum rise in the oxygen consumption. 

 We have already observed (table 181) that inside of 40 minutes the 

 quotient rose from 0.72 to 1.05 and remained at a rather high value 

 for at least two subsequent observations, the quotients being 0.98 

 and 0.93. Still another illustration of this lack of evidence as to 

 glycogen storage is supplied by the levulose experiment with L. E. E. 

 on May 22, 1911 (see table 180). Although the post-absorptive quo- 

 tient of 0.77 was the lowest obtained in this series, the ingestion of 100 

 grams levulose produced very nearly the largest excess carbon dioxide, 

 namely, 23.2 grams, 3.1 grams excess oxygen, and 21 calories of excess 

 heat (see table 175). 



It is a source of regret that the series of experiments with carbo- 

 hydrates did not include a larger number with both glycogen-poor 

 and glycogen-rich subjects. As has been shown by previous tests in 

 this laboratory, 1 it is perfectly feasible to obtain a glycogen-poor con- 

 dition by one or two days of carbohydrate-free diet. Durig, with his 



s, Peabody, and Fitz, Journ. Med. Research, 1916, 34, p. 263. 



