TISSOT AND BENEDICT METHODS. 



151 



were collected and analyzed in the same manner as in the previous com- 

 parison with the tension-equalizer unit. The periods with the two 

 forms of apparatus were either alternated or in series, and usually of 

 about 15 minutes duration, with a preliminary ventilation of approxi- 

 mately 5 minutes for each period. 



The pulse-rate was obtained as usual by means of a Bowles stetho- 

 scope, with ordinarily 5 counts in each 15-minute period. In the 

 periods with the spirometer unit the respiration was recorded from the 



MAMMM KSWflCW OUCTOTT- 



FIG. 43. Probability curves for the series of comparison experiments with the tension-equalizer 

 unit and the Tissot apparatus. 



The ordinates indicate the percentage of the total number of periods and the abscissse the 

 percentage of variation from the average. 



spirometer bell; with the Tissot apparatus, the records were made from 

 the chest pneumograph as in the previous comparison. Except in the 

 experiments with E. W. H., the muscular activity was recorded from 

 a pneumograph placed about the hips of the subject, as in the first series 

 of comparisons with the Tissot apparatus. The subjects were all assis- 

 tants in the Laboratory, with the exception of J. H. H., and had acted as 

 subjects in previous respiration experiments with the spirometer unit. 

 J. H. H. was familiar with both of the apparatus compared, although he 

 had never been used before in a comparison experiment. 



