120 



COMPARISONS OF RESPIRATORY EXCHANGE. 



The statistics of the 11 comparisons follow. Mr. J. A. Riche carried 

 out the experiments with the Zuntz-Geppert apparatus and made all 

 the air analyses. 



In addition to the data which have been given in the previous com- 

 parisons, the figures are also given for the total ventilation of the 

 lungs per minute, reduced to 0° C. and 760 mm. pressure, and the vol- 

 ume per respiration calculated to 37° C. and atmospheric pressure, 

 corrected for the tension of aqueous vapor in the lungs. The composi- 

 tion of the expired air, as obtained from the Zuntz-Geppert gas-analysis 

 apparatus, is also included in the table for the periods in which the 

 Zuntz-Geppert respiration apparatus was used. These figures repre- 

 sent the average of two analyses, agreeing usually to within 0.04 per 

 cent for both the carbon dioxide and the oxygen. 



STATISTICS OF EXPERIMENTS. 



T. M. C, June 24, 1910. — Tension-equalizer unit, 4 periods; Zuntz-Geppert 

 apparatus, 3 periods; preliminary period, 4 minutes; apparatus alternated. 

 But few counts of the pulse-rate in each period. Respiration-rate recorded 

 by pneumograph; uniform in character. Rate of preliminary ventilation for 

 20 liters with Zuntz-Geppert apparatus: 



T. M. C, June 29, 1910. — Tension-equalizer unit, 3 periods; Zuntz-Geppert 

 apparatus, 3 periods; preliminary period, 18 minutes; apparatus alternated. 

 Subject stated that during first period he felt as if he were breathing against 

 pressure and that there was so much air in the tension equalizer that his breath- 

 ing was necessarily shallow for a short time. No difficulty was experienced in 

 the following periods with this apparatus. Only a few counts of pulse-rate 

 in each period; uniform in character. Respiration-rate obtained with pneu- 

 mograph; uniform for individual periods. Rate of preliminary ventilation 

 for 20 liters with Zuntz-Geppert apparatus: 



J. J. C, June 8, 1910. — Tension-equalizer unit, 4 periods; Zuntz-Geppert 

 apparatus, 4 periods; preliminary period, 35 minutes; apparatus alternated. 

 In third period with tension-equalizer unit, subject very sleepy. Respiration- 

 rate counted by observer; in all periods but one very uniform, but in third 

 period with Zuntz-Geppert apparatus it showed a tendency toward irregu- 

 larity. 



