240 FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



100 grams of sucrose does not rest upon the summation effect of the 

 resultant dextrose and levulose and the heat production due to hydrol- 

 ysis, but that there must obviously be a compensation. Furthermore, 

 the cells may refuse to react to the indirect stimulus of the result of 

 hydrolysis and the direct stimulus of the two sugars on the basis of a 

 summation effect. With practically all of the sugars except levulose, a 

 somewhat decreased effect was found with the smaller amount of sugar. 

 With levulose, therefore, we have a specific property entirely different 

 from that found with the other sugars and in all probability we have 

 here an intermediary metabolism which may perhaps best be consid- 

 ered in connection with the study of the respiratory quotient. 



THE RESPIRATORY QUOTIENT AFTER INGESTION OF CARBOHYDRATES. 



Although the basal values for the respiratory quotients for the calo- 

 rimeter experiments were not secured in all cases on the same day, 

 quotients considerably above 0.90 were frequently obtained in the food 

 experiments, which led to the reasonable assumption that there was a 

 pronounced rise in this relationship, since the respiratory quotient for 

 normal individuals in the post-absorptive condition is not far from 0.81 

 to 0.83. In the respiration experiments a careful study of the respira- 

 tory quotients for short periods could be made; these have been recorded 

 in tables 179 to 182 and show the time relations as well as the height of 

 the quotients. In these tables we are considering only the quotients 

 obtained in experiments with 100 grams of carbohydrate. 



DEXTROSE. 



The respiratory quotients for 10 experiments with dextrose are given 

 in table 179. As will be seen from the protocols of these experiments, 

 the post-absorptive value for the respiratory quotient was in practically 

 every case an average of two or three reasonably agreeing periods. 

 These values ranged from the low quotient of 0.70 to 0.87 with an 

 average of 0.80. If we study the course of the respiratory quotient 

 in the experiments, we find that shortly after the carbohydrate was 

 given there was in practically every case a pronounced tendency for the 

 quotient to reach a maximum about the second or third hour, and 

 to fall off thereafter. It should be remembered, in studying these 

 quotients, that each value depends upon the determinations of a single 

 period and hence the general picture alone should be considered. The 

 rise followed by a fall is so clear, however, as to leave no doubt as to the 

 general course of the quotient after the ingestion of dextrose. An 

 examination of the average values shows that within 20 minutes of the 

 beginning of the experiment there was a slight fall from the average 

 basal quotient of 0.80, which was followed by a steady increase until 

 the maximum of 0.92 was reached in 2 to 2| hours; subsequently there 

 was a tendency for the quotient to decrease. 



