182 



COMPARISONS OF RESPIRATORY EXCHANGE. 



TABLE 29. Respiratory exchange in comparison experiments ivith mouth-breathing and nose- 

 breathing Benedict respiration apparatus (spirometer unit). (Without food.) Continued. 



The variations between the averages for each day are given in table 

 30, the results obtained with the nosepieces being taken as the base- 

 line. Both the carbon-dioxide elimination and the oxygen consump- 

 tion were higher with the mouthpiece in four out of five experiments, 

 while the pulse-rate was higher in three out of the four experiments in 

 which this factor was observed. It will be noted that the individual 

 variations between the averages are not large, the greatest being with 

 P. F. J. on July 10, when the difference between the averages for the 

 oxygen consumption is 13 c.c. This greater difference is caused by the 

 higher value obtained in the last period of the experiment, when the 

 oxygen consumption was notably higher than in the other two periods 

 with the mouthpiece. Two low values were obtained for the carbon- 

 dioxide elimination, one with J. K. M. in the second period with the 

 nosepieces on July 9, and one with P. F. J. in the third period with the 

 nosepieces on July 10. In both of these instances the subject was 

 somewhat drowsy and the ventilation of the lungs was consequently 

 irregular. 



