EARLIER COMPARISONS OF RESPIRATION APPARATUS. 



11 



Durig points out that the results agree very well, but calls attention 

 to the fact that part of the experiments with the respiration calorimeter 

 were made after food had been taken and a part with the subject fast- 

 ing, and that all were during sleep. He also makes note of the fact 

 that with the Zuntz-Geppert apparatus the skin respiration is not 

 measured, but that this can scarcely be 1 per cent. The subjects with 

 each apparatus were different, so that variations in body-weight and 

 nationality may come into play as well as difference in respiration 

 apparatus. 



Benedict and Joslin 1 have compared the results of the respiratory 

 exchange of 5 normal subjects obtained with the bed calorimeter and 

 the Benedict respiration apparatus 2 in a reclining position and in the 

 post-absorptive state, i. e., 12 hours after the last meal. 3 The results 

 are given in table 2. The figures were obtained by averaging all of 

 the data for these five subjects which were available at the Nutrition 

 Laboratory when the comparison was made. The experiments were 

 not carried out expressly for the purpose of comparison, but were 



TABLE 2. Comparison of the metabolism of normal individuals as determined by 

 the bed calorimeter and the respiration apparatus (Benedict and Joslin). 



on different days and under different conditions of nourishment. It 

 will be noted that the above figures agree fairly well with those cal- 

 culated by Durig from experiments with the respiration calorimeter 

 and the Zuntz-Geppert apparatus. 



A similar comparison was made by Benedict and Joslin of the respi- 

 ratory exchange of diabetics. The average results for 14 cases with 

 different degrees of severity of the disease were as follows : With the 

 bed calorimeter, 3.11 c.c. carbon dioxide produced per kilogram of 

 body-weight per minute and4.13 c.c. oxygen consumed; with the Bene- 

 dict respiration apparatus, 3.13 c.c. carbon dioxide produced and 4.15 

 c.c. oxygen consumed. The results with both diabetic and normal 

 subjects agree on the average remarkably well. 



Loeffler 4 gives measurements of the respiratory exchange of Gigon 

 obtained with different apparatus at different times. The apparatus 

 used were the Sonden-Tigerstedt chamber, the Jaquet chamber at 



'Benedict and Joslin, Carnegie Inst. Wash. Pub. 136, 1910, p. 173. 

 'Benedict, Am. Journ. Physiol., 1909, 24, p. 345. 

 3 Benedict and Cathcart, Carnegie Inst. Wash. Pub. 187, 1913, p. 31. 

 4 Loeffler, Archiv l.d. ges. Physiol., 1912, 147, p. 203. 



