MUELLER AND TISSOT VALVES. 



205 



higher. This subject apparently did not breathe normally with the 

 Mueller valves, the respiration-rate being only about 10 per minute, 

 while the normal rate for J. H. H. on the same day was 19 per minute. 

 This fact, together with the larger total ventilation, indicates that the 

 effective ventilation of the lungs was greater with the Mueller valves 

 than with the Tissot valves; consequently more carbon dioxide would 

 be eliminated with the former valves. 



The percentage variation of each individual period from the average 

 of the experiment has been calculated for the values for each apparatus 



6 



10 •* 12 13 14 15 16 



PER CENT OF VARIATION 



Fig. 56. — Probability curves for the series of comparison experiments with the Tissot valves 



and the Mueller valves. 

 The ordinates indicate the percentage of the total number of periods and the abscissa} represent 

 the percentage of variation from the average. 



and the results given in the form of curves in figure 56. The carbon- 

 dioxide elimination has about the same uniformity with both sets of 

 valves, while the oxygen consumption, respiratory quotient, and respi- 

 ration-rate are somewhat more uniform with the Mueller valves. The 

 pulse-rate, however, is more uniform with the Tissot valves. There is 

 not a very marked difference in the uniformity of results with either the 

 total ventilation or the volume per respiration. 



In general, it may be stated as a result of this series of comparisons 

 and the one preceding, that it is possible to obtain entirely normal 



10 II 12 13 



