178 



COMPARISONS OF RESPIRATORY EXCHANGE. 



lower. The first four subjects showed a tendency to a slightly higher 

 respiration-rate with the mouthpiece than with the nosepieces while 

 with K. H. A., the reverse was true. The differences in the respiration- 

 rate were not marked, however, in any of the experiments. With the 

 first three subjects the pulse-rate was slightly higher in the mouthpiece 

 periods than in those with the nosepieces. With H. F. T., the pulse- 

 rate was slightly lower with the mouthpiece, while with K. H. A. it 

 varied. 



It must be noted that all of these subjects were fairly well- trained. 

 The first, J. J. C., had been used in a great many experiments; as 

 previously stated, on account of his tendency to fall asleep during an 

 experiment, it was difficult to obtain the same degree of wakefulness 



TABLE 28. Variations of average results obtained with mouth-breathing from those obtained 

 with nose-breathing (tension-equalizer unit) 



throughout a series of periods. F. G. B. and T. M. C. were both well 

 trained in respiration experiments and accustomed to apparatus for 

 nose- and mouth-breathing. As has already been noted, H. F. T. 

 was a peculiar subject because of his occasional apnoeic respiration. 

 It is probable that with the mouthpiece he had a tendency to breathe 

 more regularly than with the nosepieces. With this subject the carbon- 

 dioxide elimination was usually higher with the mouthpiece than with 

 the nosepieces. K. H. A. was also familiar with the apparatus; he had 

 no peculiarities of respiration and was able to maintain nearly the 

 same degree of quietness and wakefulness throughout the experiments. 

 In these comparisons the preliminary period of breathing through 

 the particular appliance being tested was not very long, continuing 

 usually less than 5 minutes. Consequently, if there were a tendency 

 shown with the mouthpiece toward deeper breathing or toward an 

 exaggerated respiration, it would have been apparent, as the period 

 began so soon after the mouthpiece was inserted that there was no 



