158 
PHYSIOLOGY: H. M. SMITH 
minute carried the air through a pipe extending from the front of the chamber 
to a drier and thence back into the rear of the chamber. In this pipe of 
moving air was placed the psychrometer and from it the gas samples were with- 
drawn for analysis. 
During the period of walking pulse records were continuously made by 
means of electrocardiograms. 
The carbon dioxide was determined in duplicate by means of two Haldane 
portable gas analysis apparatus, while the oxygen was found by means of the 
Sonden apparatus. 
Two groups of 11 and 12 men respectively were under investigation. One 
squad, designated as the diet squad, was on a reduced ration from October 4 
to February 3, while the other squad, known as the control squad, acted as a 
control until January 8 when it also went on a reduced diet until January 28. 
The first experiment was made on January 6 with the 12 men of the control 
squad two days before their reduction of diet began. Each man walked in 
the chamber for twenty-four minutes at a rate close to 69.5 meters per minute. 
After a preliminary period of four minutes, during which time the necessary 
TABLE 1 
Reduced Diet and Heat Required per Man During Horizontal Walking, Rate 69. 
Meters per Minute (2.5 Miles per Hour) 
SQUAD 
CONDITION 
TOTAL HEAT 
REQUIRED PER MAN 
PER KILOMETER 
HEAT REDUCTION 
FROM NORMAL 
cal. 
per cent 
Control. . . . 
Normal 
62.2 
20-day diet 
53.5 
14 
Diet 
4-month diet 
48.4 
22 
adjustments were made, the experiment proper began and continued for 
twenty minutes. The gas samples were drawn at the start and end of this 
twenty-minute period and from the increase in the percentage of C0 2 and the 
decrease in the percentage of O2 the respiratory quotient was found and the 
energy expended was computed. 
The average total heat, thus measured, figured on a kilometer basis, is given 
in table 1 and amounts to 62.2 calories. 
After this squad had been on a reduced diet for twenty days the experi- 
ment was repeated and it was then found to cost each man on an average 53.5 
calories per kilometer. No experiment was made with the diet squad in 
September as the chamber was not in readiness at the beginning of the study, 
but on February 3 after four months' dieting an experiment made under the 
same conditions as the two preceding showed an average expenditure of 48.4 
calories per kilometer. 
As the average normal weights of the members of the two squads before 
dieting began differed from each other by only 0.5 kilogram, and since the 
basal metabolism of the two squads as determined in a large respiration cham- 
