166 Metabolism of Healthy Man. 



usually asleep. The carbon-dioxide excretion in the first experiment, when 

 no food had previously been taken, amounted to 19.9 grams per hour. The 

 subject had a body-weight of 67.2 kilos. In 4 other experiments the carbon- 

 dioxide excretion per hour from 8 p. m. to 8 a. m. was 23.5, 22.7, 24.1, and 



25.8 grams, respectively. These experiments are somewhat complicated, how- 

 ever, as food was ingested immediately preceding some of the experiments. 



While, as has been pointed out above, it is of doubtful value to compare 

 experiments made with a subject in a closed chamber with those made on a 

 sleeping subject wearing a mouthpiece, owing to the difficulties of guarding 

 against leakage around the mouth or nose when the muscles of the face are 

 relaxed, nevertheless the experiments made with our apparatus may properly 

 be compared with experiments in which the Zuntz-Geppert apparatus was used 

 with subjects awake. With the Zuntz-Geppert apparatus the subject, usually 

 well-trained, lies quietly resting on a couch with the greatest muscular relaxa- 

 tion 12 hours after the last meal, and consequently the metabolism is at a very 

 low point. For purposes of comparison, reference can be made to the table on 

 page 156 which is copied directly from an article by Loewy. 1 These results are 

 taken chiefly from the researches of Magnus-Levy and Falk and others of the 

 Zuntz school. The average production of carbon dioxide per kilogram of body- 

 weight per minute with these men was found to be 2.96 c. c, which agrees re- 

 markably with the value obtained with men when sleeping in the respiration 

 chamber at Wesleyan University, namely, 3.01 c. c. The carbon-dioxide produc- 

 tion per square meter of body-surface can also be compared with the experiments 

 made with the Zuntz-Geppert apparatus. Thus, the average of the experiments 

 given in the table on page 156 was 95.7 c. c. per square meter per minute. The 

 average of the results for the sleeping experiments here reported was 98.6 c. c. 



The variations in the results obtained with the Zuntz-Geppert apparatus 

 were somewhat larger than those obtained by us. Thus, the carbon-dioxide 

 production per kilogram and per minute by the subjects in the table on page 

 156 ranged from 2.17 c. c. with subject No. 17 to 4.18 c. c. with subject No. 10. 

 In the experiments on sleeping man reported by us the variations extend only 

 from 2.35 c. c. to 3.64 c. c. Considering the excretion per square meter of 

 body-surface per minute the variations in the table on page 156 ranged from 



76.9 c. c. with subject No. 17 to 133.2 c. c. with subject No. 10, while with 

 the sleeping men here reported the range is but from 83.9 to 118.4 c. c. 



Influence of Previous Musculae Activity upon the Carbon-Dioxide Elimination 



during Sleep. 



In many of the experiments made at Wesleyan University the night periods 

 were preceded by day periods in which there were great variations in the 

 muscular activity of the individuals. During the day the subject may have 

 been at rest and either fasting or with food; or he may have had muscular 



Loewy, Oppenheimer's Handbuch der Biochemie, Jena, 190S, 4, p. 179. 



