Carbon-Dioxide Elimination. 



169 



muscular work, particularly after a clay of such severe work as was performed 

 in the experiment with A. L. L. previously referred to, the subject would sleep 

 quietly and, indeed, more soundly than usual. 



It is greatly to be regretted that during these experiments the pneumograph 

 and stethoscope for counting the respiration-rate and heart-beat were not used, 

 for it would have been extremely interesting to note the variations in pulse 

 and the respiration-rate under the conditions cited above. The increased 

 muscular tonus, which may continue for some time after severe muscular work, 

 may account without further explanation for the noticeable increase in the 

 carbon-dioxide production following severe, and very severe, muscular work. 

 While it has commonly been believed that the carbon-dioxide production rap- 

 idly, and indeed almost immediately assumes a normal level after the work is 

 finished, the evidence as set forth here would imply that there was a consid- 

 erable increase in the carbon-dioxide excretion. This increase may be due 

 to the excretion of previously formed carbon-dioxide, which is but slowly swept 

 out of the system, or it may be due to the continuation of increased muscular 

 tonicity and possibly increased metabolism following the stimulation resulting 

 from the long-continued severe muscular work. The cause for this increase 

 has not yet been settled, and the problem is certainly worthy of further ex- 

 perimentation. 



Minimum Elimination of Carbon Dioxide during Sleep. 

 In the data recorded in table 67, the values are all given for the period from 

 1 a. m. to 7 a. m., and it is there assumed that sleep was continuous throughout 

 this period. The analyses were usually made in 2-hour periods, and conse- 

 quently we have 3 periods during sleep in each night. An examination of the 

 detailed statistics shows that in many instances there was a minimum produc- 

 tion of carbon dioxide during these periods which is somewhat less than the 

 average reported in table 67. It is of interest, therefore, to compare the mini- 

 mum carbon-dioxide production of a number of individuals during the night. 

 In the following statement the minimum carbon-dioxide elimination per hour 

 by different individuals during sleep, between 1 a. m. and 7 a. m., is given. 

 The lowest minimum carbon-dioxide production found for any individual in 

 1 hour during sleep was 15.3 grams on 1 night with the subject S. A. B. The 

 highest minimum carbon-dioxide production is found to be 25.3 grams with 

 the subject H. A. 



Grams. 



w. o 



D. W. . 

 J. C. W 



A. 



H. 

 A. 

 H. 

 A. 



C. K. 

 L. L.. 

 P. ... 



W. S. 



Grams. 

 a 19.9 



23.5 



20.1 



22.9 



25.3 

 J 21.0 



17.4 



O. 



s. 



H. 

 H. 

 H. 



F. T. 



A. B. 



E. S. 



R. 



L. 



I). 

 K. 



Grams. 



x 22.7 

 15.3 

 20.5 

 18.3 

 17.5 



Average per hour in minimum 6-hour period. 



