154 COMPARISONS OF RESPIRATORY EXCHANGE. 



both series of periods. Average barometric pressure, 755.2 mm.; average 

 temperature of air in apparatus, 16.5 C. 



J. H. H,, April 16, 1913. Tissot apparatus, 3 periods; spirometer unit, 



3 periods; preliminary period, 1 hour 6 minutes; periods with each apparatus 

 in series. Mouthpiece used. Subject said he noted but little difference 

 between the apparatus. Pulse-rate very uniform. Normal respiration-rate 

 19 to 20 per minute; respiration very uniform in character throughout experi- 

 ment. Average barometric pressure, 751.8 mm.; average temperature of air 

 with Tissot apparatus, 17.6 C.; with spirometer unit, 20 C. 



J. H. H., April 17, 1913. Tissot apparatus, 4 periods; spirometer unit, 



4 periods; preliminary period, 1 hour 12 minutes; apparatus alternated. 

 Mouthpiece used. Pulse-rate very uniform. Normal respiration-rate 22 

 per minute; respiration in experiment uniform in all periods. Average baro- 

 metric pressure, 756 mm.; average temperature of air in apparatus, 18.4 C. 



DISCUSSION OF RESULTS. 



The results of the comparisons of the respiratory exchange as 

 measured with the Tissot apparatus and the spirometer unit are given 

 in table 23. The grand averages for the two methods show a dif- 

 ference of 2 c.c. for the carbon-dioxide production, that for the Tissot 

 apparatus being 192 c.c. and for the spirometer unit 190 c.c. The 

 values for the oxygen consumption vary 9 c.c., being 242 c.c. for the 

 Tissot apparatus and 233 c.c. for the spirometer unit. The average 

 respiratory quotients are within 0.02, i. e., 0.795 for the Tissot appa- 

 ratus and 0.815 for the spirometer unit. The other factors agree very 

 fairly, the pulse-rate and respiration-rate for the Tissot apparatus being 

 60.5 and 13.9 respectively and for the spirometer unit 60.5 and 12.4 re- 

 spectively. The ventilation of the lungs is almost identical with the two 

 forms of apparatus, 5 liters and 4.96 liters, but the volume per respira- 

 tion is somewhat smaller with the Tissot apparatus, this being 445 c.c. 

 as compared with 509 c.c. 



