210 COMPARISONS OF RESPIRATORY EXCHANGE. 



type of respiration are given in figures 64 and 65. Average barometric pres- 

 sure, 766.8 mm.; average temperature of air in apparatus, 19.4 C. 



J. K. M., October 31, 1912. Without dead space, 3 periods; with dead space, 

 3 periods; first, second, and fourth periods without dead space, remaining 

 periods with dead space. Subject noted no difference between the two 

 conditions and was so unconscious of the change that he supposed one of the 

 periods with an increased dead space to be a normal period. Pulse-rate 

 varied somewhat in the different periods, the ranges varying from 6 to 15 beats 

 per minute. The variations in pulse-rate were due to drowsiness and the 

 necessity of waking subject occasionally. Respiration regular in all but fourth 

 period. Average barometric pressure, 762.2 mm. ; average temperature of air 

 in apparatus, 19.6 C. 



FIG. 65. Type of respiration of subject J. K. M. without additional dead space on 

 September 21, 1912. Original size. 



J. B. T., October 26, 1912. Without dead space, 3 periods; with dead space, 

 3 periods; first, second, and fourth periods without dead space, remaining 

 periods with dead space. Subject somewhat active previous to third period 

 with normal dead space, talking and moving about; this may account for the 

 somewhat higher metabolism shown in that period. Respiration-rate regular, 

 except in first and third normal periods; in the first period it decreased in 

 rapidity toward the end; in the third normal period it was sometimes deep 

 and slow, then rapid and shallow. Average barometric pressure, 753.8 mm. ; 

 average temperature of air in apparatus, 18.9 C. 



J. B. T., November 1, 1912. Without dead space, 3 periods; with dead 

 space, 3 periods; first, second, and fourth periods without dead space, remain- 

 ing periods with dead space. Subject noted no difference in breathing with 

 the two conditions; he stated he was very comfortable throughout the experi- 

 ment. Pulse-rate fairly uniform in all periods; respiration uniform in both 

 character and rate in all periods. Average barometric pressure, 756.4 mm. ; 

 average temperature of air in apparatus, 17.5 C. 



STATISTICS OF EXPERIMENTS WITH AN INCREASE IN DEAD SPACE OF 135 C.C. 



T. M. C., November 8, 1912. With dead space, 3 periods; without dead 

 space, 3 periods; periods with the two methods alternating. New form of 

 glass nosepieces used 1 and tested for tightness with soapsuds. Pulse-rate in 

 first period ranged from 68 to 76 ; in other periods it was uniform. Respiration 

 both in depth and rate remarkably uniform in the individual periods. Sub- 

 ject said there was no difficulty in breathing, but the respiration was deeper 

 than usual. Sections of the respiration records showing the two types of 

 breathing are reproduced in figures 66 and 67. Average barometric pressure, 

 747.8 mm. ; average temperature of air in apparatus, 20.3 C. 



P. F. J., November 7, 1912. With dead space, 3 periods; without dead 

 space, 3 periods; periods with and without additional dead space, alternating. 



^ee p. 62. 



