202 



COMPARISONS OF RESPIRATORY EXCHANGE. 



alternating. Subject found breathing with Mueller valves more difficult. 

 Pulse-rate fairly uniform, except in first period with Tissot valves, when it 

 varied from 54 to 61. Average normal respiration-rate before experiment, 

 19 per minute. Rate during individual periods uniform, but differed with the 

 two types of valves. The character of the respiration for the two methods 

 of breathing is shown in figure 55, in which portions of the curves obtained for 

 periods 4 and 5 are given. Average barometric pressure, 762.4 mm. ; average 

 temperature of air in apparatus, 17.1° C. 



DISCUSSION OF RESULTS. 



The results of the comparison experiments with the Mueller valves 

 and the Tissot valves are given in table 37. The general averages show 

 that the respiratory exchange is almost identical with the two types of 

 valves. The volume per respiration is noticeably higher with the 

 Mueller valves, this being accounted for in part by the lower respiration 

 rate and the larger dead space with those valves. 



Table 37. — Respiratory exchange in comparison experiments with Tissot valves and Mueller 

 valves using Tissot spirometer. (Without food.) 



