NUTRITION LABORATORY. 307 



life was similar to that of a frog in which the cerebral hemispheres had been 

 removed. He therefore did not develop his musculature as would a normal 

 infant of the same age, and as a result his body was made up practically of fat 

 and bones with but a small amount of muscle. The vital functions of this 

 infant were carried on at a low plane, because its existence was purely reflex. 

 The infant showed a very greatly decreased metabolism when compared to 

 normal infants of approximately the same age and weight. 



(14) A comparison of methods for determining the respiratory exchange of man. Thorne 

 M. Carpenter. PubHcation No. 216, Carnegie Institution of Washington (1915). 



This publication gives the results of an extensive series of investigations 

 upon the comparative value of a number of methods used for the determina- 

 tion of the respiratory exchange of man. The first part contains a review of 

 the previous work of other investigators and a detailed description of the 

 methods and apparatus used in the research reported, viz: bed respiration 

 calorimeter; the two forms of the Benedict universal respiration apparatus, 

 i. e., tension-equalizer unit and spirometer unit; Zuntz-Geppert, Tissot, and 

 Douglas apparatus; the Haldane gas-analysis apparatus; and minor accessory 

 apparatus. The results of the various comparisons of apparatus follow. The 

 bed respiration calorimeter was made the standard for normal respiratory 

 exchange. Normal, healthy young men were used as subjects and the com- 

 parisons of any two apparatus were made on the same day under like con- 

 ditions of muscular repose and nutrition. The carbon-dioxide elunination, 

 oxygen absorption, respiratory quotient, pulse-rate, respiration-rate, and, 

 when possible, total ventilation of the lungs and volume per respiration were 

 determined. 



A series of comparisons of the respiratory exchange obtained with the bed 

 calorimeter and tension-equalizer unit showed agreement in the values for the 

 carbon-dioxide elimination and oxygen absorption, but an agreement of the 

 respiratory quotients was more difficult to obtain. It was believed that this 

 was due more to the difficulty of determining the oxygen consumption in the 

 bed calorimeter than to an actual difference in the character of the respiratory 

 exchange. The two forms of the universal respiration apparatus gave like 

 results. Comparisons of the tension-equafizer unit with the Zuntz-Geppert 

 and the Tissot apparatus, and of the spirometer unit with the Zuntz-Geppert, 

 Tissot, and Douglas apparatus showed that the results of the respiratory 

 exchange obtained with all of these apparatus were entirely comparable. A 

 comparison of the respiratory exchange in mouth-breathing and nose-breath- 

 ing with the two forms of the universal respiration apparatus and with the 

 Tissot apparatus and in mask-breathing and nose-breathing with the spirome- 

 ter unit showed that the respiratory exchange is practically identical with 

 the various breathing appliances. A study of the Mueller valves in compari- 

 son with the spirometer unit and with the Tissot valves indicated that values 

 obtained with the Mueller valves are reliable when subjects have become 

 accustomed to their use. The addition of dead air-space to the spirometer 

 unit in amounts up to 225 c.c. had no effect upon the respiratory exchange. 

 The omission of the use of the automatic siphon counterpoise on the Tissot 

 spirometer was also without effect upon the respiratory exchange. 



Tables of variations and probability curves for the various determinations 

 made are given and discussed for nearly all of the comparisons. The pubUca- 

 tion concludes with a critical discussion of the sources of error; the advantages 

 and disadvantages of the various apparatus and methods used; breathing 

 appliances; valves; gas-analysis apparatus; and the accuracy and interpreta- 

 tion of the results of experiments on the respiratory exchange of man. 



