Metabolism Experiment Xo. 68. 



69 



The amount of water vaporized does not appear either in table 30 or in the 

 table recording the data concerning water-vapor, i. e., table 21, but it may be 

 computed by adding to the total water of respiration and perspiration the 

 amount of water lost by the chair, bedding, and absorbers, or if these latter 

 gain water, by subtracting the amount gained from the total water of respiration 

 and perspiration. 



The heat produced on the two days of this experiment, recorded in column d, 

 is nearly the same, there being an increase of but 50 calories on the second day 

 over the first. The uniformity of the heat production signifies a close approxi- 

 mation to constant muscular activity. 



Balance of Energy. 

 The total energy resulting from the katabolism of protein, fat, and glycogen 

 on the different days is shown for this and the following experiments in 

 exactly the same form in table 31 as for experiment ISTo. 59. Since the source 

 of the figures was explained in detail (see p. 51), further explanation seems 

 unnecessary. It may be well, however, again to call attention to the fact that 

 while fat and glycogen are completely oxidized in the body and their energy 

 converted to kinetic energy, in the case of the protein, there is an appreciable 

 part of the energy excreted in a partially unoxidized form, namely, in the 

 unoxidized compounds of the urine. In order, therefore, to construct a complete 

 balance of the energy derived from all sources with the total heat production, it 

 is necessary to take into consideration the potential energy of the urine. 



Table 31. Comparison of energy derived from katabolized body material with total 

 heat production Metabolism experiment No. 68. 



On the first day of the experiment, the energy derived from the different 

 sources is computed to be 14 calories larger than the total heat production, 

 a disagreement of -4-0.6 per cent. On the second day, on the contrary, the 

 energy derived from the different sources is computed to be 38 calories less 

 than the total heat produced, a discrepancy of 1.7 per cent. The average 

 of the two days gives a discrepancy of but 12 calories, which is 0.5 per cent 

 of the total heat production, 



