150 
PHYSIOLOGY : BENEDICT AND ROTH 
For subjects we selected 12 young men from a considerable number of 
volunteers from the student body of the International Y. M. C. A. College in 
Springfield, Mass. The average age of the men was twenty-three years. 
For a period of four months these men were kept upon a much restricted diet, 
with an energy content of approximately one-half to two-thirds of their 
caloric requirements prior to the test. During the first few weeks there was a 
distinct drop in body weight. When the body weight had fallen on the aver- 
age 12%, the calories in the diet were increased so as to prevent further loss 
in weight. The measurement of the caloric consumption at this sustained 
weight level would indicate the true caloric requirement for maintenance. 
For control 12 men from the same student body, living under exactly the 
same conditions save for the dietetic restrictions, were likewise studied and 
their food intake occasionally measured for periods of four or five days. 
It was impossible to place all the men in respiration chambers and study 
their metabolism during the entire twenty-four hours, for it was realized that 
these men were, first, college students, and second, volunteers for scientific 
experimentation, and that their college duties, both intellectual and physical, 
must be carried out; hence they were all cautioned at the beginning of the 
study not to restrict their activities in any way. Even with the best conditions 
it could not be assumed that the muscular activity of both groups of men 
would be exactly alike throughout the period of observation. It thus seemed 
best to make the measurements of the metabolism upon a uniform basis, ex- 
cluding uncertain and, more particularly, uneven muscular activity. For this 
purpose all of the first group of men were studied during periods of complete 
muscular repose and without food in the stomach, so as to obtain the basal 
metabolism practically every morning from the 27th of September, 1917, to 
the 3rd of February, 1918. The individual measurements were controlled 
by a group study with a large respiration chamber in the Nutrition Laboratory 
in which the 12 men slept every alternate Saturday night; the metabolism 
during deep sleep was thus obtained. No individual tests were made with 
the control squad, but group measurements were obtained on the alternate 
Saturday nights and used for comparison with the group results obtained for 
the diet squad. 
Prior to the dietetic restriction, the basal metabolism, measured inside the 
large respiration chamber at night, was the same with the first and second 
squads, thus giving admirable proof that a group of 12 men was sufficiently 
large for our purpose. In addition to the observations on weight and basal 
metabolism, records were obtained of the total nitrogen in the food, feces, 
and urine during the entire four months, frequent observations were made of 
the pulse and respiration rate, total ventilation of the lungs, alveolar carbon 
dioxide, energy requirement for walking a definite distance at a definite 
speed, the blood (including counts of the red and white corpuscles and dif- 
ferentials, and determination of the haemoglobin), the blood pressure and 
rectal and skin temperatures. Clinical examinations were also made, as 
