134 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



The walking then continued without interruption for another 10 

 minutes, when the same procedure was followed, except that at this 

 time a sample of air was likewise drawn into the Sonden gas-analysis 

 apparatus for the determination of the oxygen present at the end of the 

 experiment. At this time a photographic record of the pulse was again 

 made. The walking continued until the samples of the air were drawn, 

 when the cover of the chamber was lifted and pressure was put upon 

 the cuff of the sphygmomanometer. At this point the treadmill was 

 stopped and the blood pressure was determined as rapidly as possible 

 during the next 2 minutes. The subject was then disconnected from 

 the respiration tambour, galvanometer leads, and step counter. On 

 leaving the chamber he was weighed and the final records of blood 

 pressure and radial pulse were made in an adjoining room. 



At the conclusion of the experiment the large ventilating fan was 

 moved up to the chamber, the windows were opened, and both the 

 room and chamber were given a thorough ventilation during the fol- 

 lowing 10 to 12 minutes. During this time preparations were made 

 for the next experiment. 



METHOD OF CALCULATING RESULTS OF THE METABOLISM EXPERIMENTS 



DURING WALKING. 



The calculation of the carbon dioxide produced was a relatively 

 simple matter. The apparent volume of the chamber was corrected 

 for any change in the level of the spirometer, this correction being 21.5 

 c.c. for each millimeter of change. From this volume was deducted 

 the air displaced by the subject, which was taken as the equivalent in 

 liters of his body-weight. The corrected volume was then reduced to 

 0° C. and 760 mm. of pressure. The percentage of carbon dioxide as 

 found by analysis and the corrected volume of the air in the chamber 

 gave the total volume of carbon dioxide present at the start; a similar 

 calculation gave the volume of carbon dioxide present at the end and 

 the difference between the amounts, divided by the time elapsed, gave 

 the carbon dioxide produced per minute. 



The calculation of the oxygen consumed was not so simple, because, 

 as stated elsewhere, the time available for each subject was limited to 

 approximately 45 minutes, which precluded a determination with the 

 Sonden gas-analysis apparatus of the oxygen present at both the 

 beginning and end of the experiment. The oxygen present in the 

 chamber at the start was obtained by computation as follows: 



It was assumed that the respiratory quotients of the normal subjects 

 would be approximately 0.85; those of the men on the restricted 

 diet were found to be more nearly 0.81. It was also assumed that the 

 air in the chamber before the cover was lowered was practically of the 

 same composition as outdoor air, this being due to the open windows 

 and complete ventilation of the chamber and room. The percentage 



