Carbon-Dioxide Elimination. 165 



In two of Liebermeister's experiments/ the subject slept, during a portion 

 of the time, and in the first experiment the carbon-dioxide production amounted 

 to 24.6 grams per hour. In the second experiment, which was made a week 

 later on the same subject, he found in 2 half-hour periods, when the subject 

 was sleeping soundly, 25.4 and 24.6 grams of carbon dioxide per hour, respec- 

 tively. The subject was 42 years of age, 177 cm. high, and weighed 68.5 kilos. 



In 6 days of experimenting with a fasting subject, Sadovyen 2 found the 

 carbon-dioxide excretion per hour during the night from 11 p. m. to 9 a. m. 

 as follows : 29.7, 36.7, 32.7, 33, 28.5, and 27 grams, respectively. On one night, 

 when the man took food, the carbon-dioxide production in that period was 32 

 grams per hour. 



In the respiration apparatus of Hoppe-Seyler, there was no opportunity for 

 the subject used by Laves 3 to lie down, and consequently, although 2 experi- 

 ments are reported as having been made between 9 o'clock at night and 7 o'clock 

 in the morning, it is highly probable that, although no direct evidence is pre- 

 sented, the subject was not soundly asleep. The carbon-dioxide production in 

 these 2 experiments was 26 and 24.5 grams per hour, respectively. 



By far the greatest number of experiments made during the night, aside 

 from those conducted in the respiration calorimeter at Wesleyan University, 

 were made in the research by Sonden and Tigerstedt. 4 In 11 experiments 

 these investigators found that the carbon-dioxide production during sleep was 

 20.5, 21.5, 24.5, 19.5, 19.5, 21, 22, 27, 22, 25.5, and 24.5 grams per hour, 

 respectively. 



Lewin, 5 using the large Pettenkofer respiration apparatus in Munich, made 

 5 experiments with a man, in which the sleeping periods covered 8 to 9 hours. 

 In these experiments, which were all made with a healthy workingman weighing 

 76 kilos, the carbon-dioxide production per hour was 26, 27, 25.5, 28, and 27 

 grams, respectively. 



During one of the experiments reported by Jaquet in the description of 

 his respiration apparatus, 6 the subject remained in the chamber throughout the 

 night and from 10 p. m. to 2 h 30 m a. m. he was sleeping, the greater part of 

 the time deeply. During this experiment, 3 periods were obtained and the 

 carbon-dioxide production per hour was 27.5, 25, and 23.1 grams, respectively. 



Exercising especial precaution to keep quiet when not sleeping and thus 

 making the experiments comparable, Staehelin 7 made a number of experi- 

 ments on himself with the Jaquet respiration apparatus at Basel, studying 

 particularly the influence of the ingestion of food. The experiments were all 

 made during the night period, when the subject was lying quietly in bed and 



1 Liebermeister, Deutsch. Archiv f. klin. Med., 1870, 7, p. 75. 



2 Sadovyen. loc. cit. 



s Laves, Zeitschr. f. physiol. Chemie, 1894, 19, p. 590. 

 * Sonden and Tigerstedt, loc. cit. 



5 Lewin, Zeitschr. f. Biol., 1881, 17, p. 171. 



6 Jaquet, loc. cit. 



' Staehelin, Zeitschr. f. klin. Med., 1906, 66, p. 201. 



