Metabolism Experiments Nos. 103-157. 



31 



Water Vaporized and Carbon Dioxide Eliminated. 

 The amounts of water vaporized inside the chamber are given in table 17. 

 No large variations are noted in the amounts of water remaining in the cham- 

 ber, and in this experiment, as in most of the others, the humidity remained 

 reasonably constant. The quantities of carbon dioxide eliminated during the 

 experiment are shown in table 18. Of special note in this table is the enormous 

 increase in the amount of carbon-dioxide residual in the chamber at the end 

 of the successive periods. This increase is altogether out of proportion to 

 the normal content in experiments of this kind. At first sight one might 

 reasonably think that the very large amount of carbon-dioxide residual in 

 the chamber in the afternoon, for example, might materially influence the 

 gaseous exchange. Fortunately there was a subsequent experiment made with 

 this subject, in which the influence of excessive amounts of carbon dioxide 



Table 18. Record of carbon dioxide Metabolism 

 experiment No. 103. 



was carefully studied. 1 From that experiment it seems highly probable that 

 the presence of a large amount of carbon dioxide does not influence in any 

 measurable amounts the excretion of carbon dioxide, and hence the quantities 

 in the last column of the table may be taken as normal results for the periods. 

 The explanation of this large increase in the residual amount of carbon dioxide 

 can in all probability be found in the fact that the soda-lime in the purifying 

 vessels had become exhausted and had not been replaced by fresh material in 

 other vessels. An examination of the nature of the ventilation system of an 

 apparatus of this type shows, however, that any carbon dioxide escaping ab- 

 sorption is not lost, but is returned to the chamber, there to be absorbed in 

 a subsequent period or accumulated, as was the case in this experiment. 



Measurements of Oxygen and Heat. 

 The data for the oxygen consumption are given in table 19. The accumula- 

 tion of a large amount of carbon dioxide in the chamber naturally affected in 

 a marked manner the residual amount of oxygen, and hence made necessary 

 rather large corrections. While the possibility of error is somewhat greater 

 with oxygen than with carbon dioxide, we have every reason to believe that 



1 The results of this experiment, which is, perhaps, the most complete of any made 

 on this subject, are reported by Benedict and Milner, U. S. Dept. Agr., Office Exp. 

 Stas. Bui. 175, 1907, p. 94. 



