Carbon-Dioxide Elimination. 



151 



drawn into these globes was subsequently analyzed, and from the analyses and 

 the volume of air the carbon-dioxide production was calculated. Unfortunately, 

 these writers did not give the body- weights of their subjects and these data 

 will be greatly missed, as may be seen later in this discussion, since the carbon- 

 dioxide production varies in general with the body-weight. The results as 

 presented by these investigators have been computed on the basis of the number 

 of grams of carbon dioxide per hour and reported elsewhere. 1 A portion of 

 the table given by Sonden and Tigerstedt is reproduced herewith (table 59). 



Using a respiration chamber containing about 1000 liters, Scharling 2 studied 

 the carbon-dioxide exhalation of a number of individuals. He confined himself 

 to experiments of 35 to 45 minutes' duration, as he feared the possible influence 

 upon the respiratory exchange of an increase in the percentage of carbon dioxide 

 in the air. The results have been calculated on the basis of carbon-dioxide 

 excretion per hour by Sonden and Tigerstedt, and certain of the results, com- 

 parable with the experiments made in the Wesleyan University chamber, are 

 given in table 60. 



Table 60. Carbon-dioxide elimination of subjects 

 in experiments reported by Scharling. 



In connection with the researches of Scharling, it should be pointed out that 

 the criticism raised by Zuntz that Scharling^s method probably gave too low 

 results should be borne in mind. Scharling himself noted a turbidity in lime- 

 water held at the opening of his air-pump. 3 



Valentin and Brunner 4 breathed for 15 minutes through a flask and then 

 analyzed its contents. In other experiments they collected the total expired 

 air in a gasometer. In his experiments on himself, Valentin, who was 33 years 

 old, exhaled with a somewhat rapid respiration 42 grams of carbon dioxide 

 per hour. The average of all experiments on both Valentin and Brunner, 6 in 

 number, showed a carbon-dioxide output of 41 grams per hour. The authors 

 point out that this agrees with the results obtained by Andral and Gavarret, 

 but they also point out that owing to the increased respiration the results are 

 somewhat too high for ordinary quiet daily respiration. 



By collecting the expired air in a glass bell-jar over a salt solution and sub- 

 sequently analyzing it, Vierordt 5 determined the total carbon-dioxide output 



1 Sonden and Tigerstedt, Skand. Archiv f. Physiol., 1895, 6, pp. 55 and 56. 



2 Scharling, Ann. der Chem. u. Pharm., 1843, 45, p. 214. 

 'Zuntz, Hermann's Handbuch der Physiologie, 1882, 4, p. 123. 



* Valentin and Brunner, Lehrbuch der Physiologie des Menschen, 1841, 1, p. 565. 

 s Vierordt, Physiologie des Menschen, Heidelberg, 1845. 

 11 



