Oxygen Consumption. 417 



With the development of the type of respiratory apparatus brought to such 

 signal success by Zuntz and associates, innumerable experiments have been 

 made in which the respiratory quotient has been determined during brief fasts. 

 It is true of the oxygen as of the carbon dioxide, that the determinations of 

 the fasting values are of importance in the interpretation of the respiratory 

 quotient in the large majority of experiments. This type of apparatus was 

 used in determining the oxygen intake of the fasting subjects Cetti and 

 Breithaupt (7). Although results were obtained for but a few minutes each 

 day and during the respiration experiment the subject was lying on a sofa, the 

 authors computed the total oxygen consumption for the 24 hours on the basis 

 of these short experiments. The amounts of oxygen consumed for the 10 

 days of Cetti's fast were 567, 501, 482, 478, 470, 467, 502, 526, 489, and 449 

 grams, respectively. These values are obtained by multiplying the quantity 

 of oxygen absorbed per minute during rest by the total number of minutes in 

 the day and no allowance is made for the variations in muscular activity, so 

 that the values can at best be only approximate. In the experiments on 

 Breithaupt, the complications of a cold and other disturbances were so notice- 

 able that the authors did not consider the computed results for the 24 hours as 

 of general value. 



Hanriot & Kichet, 132 using a different form of respiration apparatus, deter- 

 mined the oxygen consumption of a fasting man after 46 hours of fasting. 

 The amounts consumed per hour after the seventeenth, twenty-fourth, twenty- 

 ninth, and forty-sixth hours of the fast were 17.04, 16.85, 16.05, and 16.90 

 liters, respectively. The subject of the experiment weighed 50 kilograms. 

 These observations were likewise made only during short periods. 



The first direct determinations of oxygen consumed by man during 24 hours 

 are those made with the Hoppe-Seyler 133 modification of the Kegnault and 

 Eeiset apparatus, although none of the experiments reported as made in this 

 apparatus were fasting experiments. 



Zuntz has recently devised an apparatus on the Kegnault and Keiset plan 

 that can be used for small animals or infants. 134 No experiments with infants 

 have, however, as yet been reported. 



Direct determinations of the amount of oxygen consumed by man have 

 been made in a number of experiments in this laboratory during the past 3 

 years. A brief preliminary report of one of these experiments 13 has been 

 followed by a more detailed discussion of one day of an experiment with this 



132 Compt. rend, de l'Academie des Sciences (1888), 106, p. 496. 



133 Zeit. f. physiol. Chemie (1894), 19, p. 574. 



1S4 Archiv f. Physiol. (Physiol. Abth. d. Archiv f. Anat. u. Physiol.) (1905), 

 Supplement, Band, p. 431. 



135 A respiration calorimeter with appliances for the direct determination of oxy- 

 gen, 24 pages. Wesleyan University, Middletown, Connecticut. Printed, not pub- 

 lished, Aug., 1903, W. O. Atwater & F. G. Benedict. 



