150 



Metabolism of Healthy Man. 



the carbon dioxide formed in 24 hours * was approximately 1200 grams. In the 

 memoir of 1790 2 they report that the total carbon-dioxide excretion amounted 

 to approximately 600 grams. 1 



The conditions under which the experiments were made are described in only 

 too meager a manner by these writers, and we have absolutely no knowledge 

 regarding the kind of apparatus used in the experimenting other than the idea 

 given by 2 excellent drawings ascribed to Madame Lavoisier/ and consequently 

 we can judge but little of the true value of these data. 



One of the earliest methods for studying the carbon-dioxide output was to 

 exhale the gas from the lungs into a rubber bag during a specified length of 

 time and subsequently to analyze the air. This method was used in 1839 by 

 Coathupe. 4 The bag, which contained 130 cubic inches, was filled by successive 

 expirations, great care being taken to prevent the inspiration by the subject 

 of any air which he had once breathed. A sample of the air was passed into 

 a special tube with stopcocks at each end, and the carbon dioxide was absorbed 

 in limewater. Coathupe calculated that in 21 hours there were 5.45 ounces 

 avoirdupois of carbon exhaled. This corresponds to 154.5 grams of carbon, 

 which are equivalent to 566.6 grams of carbon dioxide in 24 hours. 



Table 59. Carbon-dioxide elimination of subjects in experiments reported by 



Andral and Gavarret. 



An extended series of experiments was made in 1843 by Andral and Gav- 

 arret, 8 who studied the carbon-dioxide excretion of a relatively large number 

 of different individuals. Their method involved the use of a face-mask which 

 permitted breathing either through the mouth or through the nose, and the 

 air was aspirated through this mask which was connected with 3 large glass 

 globes from which the air had previously been exhausted. The expired air 



1 Estimated from the old French weights as given in the memoir. 



2 Lavoisier and Seguin, Histoire de l'Academie des Sciences, Paris, 1790, pp. 608- 

 610. 



3 Grimaux, Lavoisier 1743-1794, Paris, 1899, pp. 119 and 129. 

 4 Coathupe, Philosophical Magazine, 1839, 3d ser., 14, p. 401. 

 n Andral and Gavarret, Ann. de Chim. et de Phys., 1843, ser. 3, 8, p. 129. 



