Energy of Body Material. 495 



matter of urine determined in a 1-day fasting experiment (No. 36) were 

 not published in that report. They were found to be 8.39, 11.12, and 2.59, 

 respectively. The ratio of heat of combustion to nitrogen has been computed 

 for the other fasting experiments published simultaneously with experiment 

 JSTo. 36, although the data were lacking for computing the ratios of heat of com- 

 bustion to carbon and organic matter. The ratio Cal. : 1ST in experiments 

 Nos. 39, 42, and the 2 days of experiment No. 51 were 8.19, 7.66, 8.19, and 

 7.08 respectively. 



Eatios of heat of combustion to nitrogen as wide as those obtained in some 

 of these fasting experiments have rarely been observed. 



A disturbance of the proteid metabolism accompanied by unusually large 

 Cal. : N ratios during residence in high altitudes was observed and reported by 

 Loewy, 167 who was able to isolate a considerable amount of amino bodies from 

 the urine. Indeed, there seemed to be a distinct relation between the quanti- 

 ties of amino bodies and the height at which the subject of the experiments 

 dwelt. While we have but little reason to expect an excessive elimination of 

 amino bodies in the urine of fasting men, the high ratio of heat of combustion 

 to nitrogen may well be explained by the formation of acids such as has been 

 pointed out in the discussion on the carbon and energy content of the urine. 



ENERGY OF KATABOLIZED BODY MATERIAL. 



In the course of katabolism during inanition, varying quantities of protein, 

 fat, and carbohydrate are disintegrated. The amounts thus katabolized have 

 been discussed in the several sections. Since these compounds are capable 

 of supplying widely varying quantities of energy to the body, it is of interest 

 to note the proportions of the total energy liberated in the body as a result of 

 the katabolism of the three compounds. 



Proportion of energy derived from different sources. The proportions of 

 the energy supplied by the protein, fat, and glycogen have been computed and 

 recorded in table 239. In this discussion the net energy of the protein, i. e., 

 the energy of the protein less that of the unoxidized material of the urine, alone 

 is considered. One possible source of error is present in this method inasmuch 

 as it is here assumed that the unoxidized material of the urine is derived 

 wholly from protein. Under normal conditions this is probably the case, 

 but with the possibilities of an acidosis as a result of partial oxidation and 

 cleavage of fat, it is obviously erroneous to deduct from the energy of the 

 protein katabolized, the energy of the urine in case a portion of the energy 

 of the urine has been derived from fat. The effect of this assumption is to 

 decrease the proportion of the total energy derived from the protein and to 

 increase the proportion actually derived from fat. Unfortunately no data are 

 at hand to show the exact magnitude of the error thus involved. 



16I Deutsch. med. Wochenschrift (1905), 48, p. 1918. 



