158 



Metabolism of Healthy Man. 



In the experiments of G-ruber * the carbon dioxide from, the total expired 

 air was absorbed in soda-lime. An experiment made on himself when he was 

 25 years of age and weighed 69 kilos showed that while at rest (sitting in a 

 chair) he exhaled carbon dioxide at the rate of 29.12 grams per hour. The 

 total carbon dioxide in 2 other experiments was 38.25 and 38.75 grams per 

 hour. In the first experiment the subject had had a cup of coffee with a small 

 piece of bread 4 hours before; the other 2 experiments were made 5 hours 

 after a heavy meal, but the author states that in the first of these 2 experiments 

 there may have been a leak. 



With the desire to study the normal production of carbon dioxide of men 

 and women of different ages, Sonden and Tigerstedt 2 carried out an heroic 

 investigation on the carbon-dioxide production of different individuals. They 

 used for this purpose a large respiration chamber, designed and built by them 

 in Stockholm. The experiments were planned to study the total respiration 

 products, particularly the simultaneous carbon-dioxide production of a number 

 of persons. To this end, from 6 to 10 people were confined in the respiration 

 chamber at the same time for experiments lasting from 2 to 8 hours, and a 

 number of experiments were also made on individuals, which extended over 

 the greater part of the 24 hours. The subjects included men and women of 

 all ages, from children to elderly people. Such results as are more or less 

 comparable with the experiments here reported are given in table 65. 



Table 65. Carbon-dioxide elimination of subjects in 

 experiments reported by Sonden and Tigerstedt. 



With a group of women having an average age of 17.69 years and a body- 

 weight of 53.9 kilos, they obtained 27.1 grams of carbon dioxide per hour. An- 

 other group, with an average age of about 30 years, and a weight of 53.9 kilos, 

 exhaled 29.1 grams of carbon dioxide per hour. 



Another series of experiments was made by Sonden and Tigerstedt on differ- 

 ent individuals during the greater part of the 24 hours, and these, together with 

 the earlier experiments made by these writers, will be frequently referred to in 

 a subsequent discussion. 



1 Gruber, Zeitschr. f. Biol., 1891, 28, p. 472. 



2 Sonden and Tigerstedt, Skand. Archiv f. Physiol., 1895, 6, p. 1. 



