EXPERIMENTS ON METABOLISM OF ENERGY. 103 
* twenty-four years old and weighed about sixty kilograms (132 
pounds). J. F.S.,a chemist, was a Canadian by birth, twenty- 
nine years old, and weighed about sixty-five kilograms (143 
pounds). 
Occupation.—In the rest experiments the subjects were as 
quiet as they well could be. Practically their only muscular 
exercise was that involved in dressing and undressing, folding 
and unfolding the bed, chair, and table, eating, caring for the 
excretory products, and weighing themselves and the absorbers. 
They did more or less reading and writing to pass the time. 
In the work experiments they spent a number of hours, gener- 
ally eight each day, driving a stationary bicycle.* It was their 
purpose to do a reasonable but not excessive amount of work. 
CLASSIFICATION OF THE HXPHRIMENTS. 
Experiments Nos. 1 and 2 with E. O., No. 3 with O. F. T. 
and 4a and 4b with A. W. S. were rest experiments, while 4c 
with A. W. S. was a work experiment. In none of these ex- 
periments were satisfactory determinations made of the outgo 
of energy. The experimental days began at different hours, 
and were not divided into six-hour experimental periods, as 
was done in all experiments after No. 4: Taking into account 
the seventeen experiments, summarized in the following tables, 
in which the measurements of the outgo of energy were con- 
sidered satisfactory, there were seven rest experiments with E. 
O., covering twenty-five days, one rest experiment with A. W. 
S., covering three days, and three rest experiments with J. F. 
S., covering nine days, making altogether eleven rest experi- 
ments, covering thirty-seven days. There were also two work 
experiments with EH. O., covering eight days, and four work ex- 
periments with J. F. S., covering twelve days, making together 
six work experiments covering twenty days. Altogether the 
seventeen rest and work experiments covered a total period of 
fifty-seven days. In addition eleven rest experiments covering 
thirty days, and two work experiments covering six days have 
been completed in connection with a separate investigation. 
Each of these experiments is divided into days of twenty- 
four hours beginning and ending at 7 A. M. Hach day is 
divided into four periods of six hours each; the first two, 
_ ealled day periods, extending from 7 A. M. to 1 P. M. and from 
Ip. M. to 7 P. M.; the last two, called night periods, extending 
from 7 P. M. to1 A. M. and from 1 A. M. to 7 A. M. 
* Excepting in experiment No. 4b, in which the subject raised and lowered a weight 
attached to a rope which passed over a pulley. 

