510 I N'FLUENCE OF INANITION ON METABOLISM. 



organic hvdrogen, and pulse is especially well marked. It would appear, then, 

 that these factors of katabolism are in a general way directly proportional to 

 the pulse rate even with the inadequate records made in this experiment, and 

 this curve emphasizes more perhaps than could any series of figures, the im- 

 portance of making records of pulse rate in metabolism experiments. Antici- 

 pating this extreme regularity between the pulse rate and the factors of meta- 

 bolism, in the experiments Nos. 79 to 89 inclusive especial care was taken to 

 secure the pulse and respiration rate (see p. 228). The protein, fat, and 

 glycogen katabolized and the amounts of the urinary constituents are shown in 

 the second set of curves. The curve for the protein obviously follows directly 

 the nitrogen of urine. The relation between the katabolism of fat and glyco- 

 gen is shown, since as the katabolism of glycogen decreases, the fat katabolized 

 increases in nearly every instance. The energy of the urine follows in a general 

 way the organic matter and the carbon, but there is little, if any, relation be- 

 tween the nitrogen and the other factors in the urine. 



ENERGY BALANCE. 



The increased accuracy in the apportionment of the katabolism between the 

 three compounds protein, fat, and carbohydrate in the experiments during 

 inanition, makes the estimate of the energy of material katabolized from the 

 body much more accurate than in the older experiments in which there was 

 no exact knowledge of the amounts of glycogen katabolized, and in all proba- 

 bility the estimated energy of material oxidized in the body computed from the 

 amounts of protein, fat, and glycogen katabolized results in much closer approx- 

 imations to the actual energy transformations than have as yet been available 

 to physiologists. 



In the experiments during inanition previously reported from this labora- 

 tory 17 the estimated energy of material katabolized was compared with the 

 heat production. The store of glycogen in this comparison was assumed to 

 have remained unaltered. Furthermore, while the heat elimination was in all 

 probability determined with reasonable accuracy the heat production was not 

 measured as accurately as in the present series of fasting experiments. 



The results show that the differences in three experiments between the esti- 

 mated energy from material actually oxidized and the net heat outgo were some- 

 what over 100 calories. In these three experiments (Nos. 36, 39, and 42), the 

 energy measured as heat was less than the estimated energy of material 

 actually oxidized in the body. The percentage error was 5.1, 5.4, and 

 5.2 per cent for the three experiments, respectively. On the other hand, 

 on the 2 days of experiment No. 51, the agreement between the energy of 

 material actually oxidized and that measured as heat was extremely close. 

 No wholly satisfactory explanation appears at present for this agreement. 



170 U. S. Dept. Agr., Office of Expt. Sta. Bui. 136. 



