Carbon-Dioxide Elimination. 



173 



during both the clay and the night, the results have been collected and pre- 

 sented in table 70. The average carbon-dioxide production during sleep per 

 hour is given in the first column, and that during the waking hours with the 

 subject at rest in the second. The results in the first two columns are copied 

 from tables 67 and 69, and the ratio of sleeping to waking is shown in the last 

 column. If the value when asleep is taken as 100, it is seen that the value 

 when at rest and awake may vary from 118 to 165 

 ratio of 100 : 140. 



The total average shows a 



Table 70. Ratio of carbon dioxide eliminated during sleep to that 

 eliminated, during waking hours in rest experiments. 



This ratio has been discussed at considerable length by Sonden and Tiger- 

 stedt. 1 In 6 experiments with normal diet the ratios found by Sonden and 

 Tigerstedt were 100: 114, 137, 147, 151, 169, and 138, respectively. Without 

 food the ratios in 5 experiments were 100 : 156, 142, 136, 132, and 143, re- 

 spectively. The average of the experiments with normal diet was 100 : 148 ; 

 without food, 100 : 142, with an average of 100 : 145, a value agreeing almost 

 identically with that found in the experiments here reported. 



Mention should be made here of the relationship between the day and the 

 night as found in the experiments of Pettenkofer and Voit, although, as has 

 been pointed out previously, the carbon-dioxide excretion was not, strictly 

 speaking, during sleeping periods. 2 The ratios found in their 10 experiments 

 on a healthy man were 100 : 137, 120, 141, 133, 131, 137, 135, 154, 107, and 

 132, respectively, the average of all these ratios being 100 : 135. 



CONCLUSIONS WITH REGARD TO THE ELIMINATION OF CARBON DIOXIDE. 



From the results of these experiments it is evident that individuals vary 

 materially in the carbon-dioxide production during the day, and even when 

 considered on the basis of body-weight or body-surface there are still noticeable 

 variations. That these variations are in large part due to variations in the 



1 Sonden and Tigerstedt, loc. cit., p. 148. 



2 Pettenkofer and Voit, Zeitschr. f. Biol., 1866, 2, p. 546. 



