PURPOSE AND PLAN OF RESEARCH. 
Second, the total changes in body nitrogen should be determined by estab- 
lishing a continuous nitrogen balance until equilibrium was subsequently 
found at the lower weight level. 
Third, there should be records of the body-weight, with observation of the 
fluctuations and the causes therefor, recognizing the fact that sharp fluctua- 
tions in body-weight may in large part be attributed to changes in the water 
content of the body. 
Fourth, a record should be made of the general physical well being, this to 
include measurements of strength. 
Fifth, since it was highly important that possible impairment of the 
intellectual and physical ability should not be overlooked, continuous and 
careful records of neuro-muscular processes should be obtained. 
In connection with such a research, the following questions naturally 
suggest themselves: 
(1) Is it possible to alter the basal metabolism by a reduced ration? 
(2) Can the body be held in nitrogen and carbon equilibrium at the lower 
level? 
(3) If such a lowering in basal metabolism is obtained by a reduction in 
diet, will the lowering be proportional to the reduction in weight, that is, if 
there is a loss of 10 per cent in body-weight, will the basal metabolism be 10 
per cent less than the normal metabolism or will the basal metabolism per 
kilogram of body-weight be unlike at the two nutritional levels? 
(4) Since the body material lost would presumably be in greater part fat, 
and thus supposedly inactive in metabolism, will the basal metabolism increase 
with the loss in weight, as would be expected, or will it decrease? 
(5) Will superimposed muscular work be done at a higher or lower cost of 
energy at an altered level of basal metabolism? 
(6) Will the stimulating effect of foodstuffs, primarily that of protein, be 
the same with reduced body-weight as with the normal body-weight? 
As the result of our research, we were able to make material contri- 
butions on the first five problems, and suggestions on the sixth may 
also be found in our data. 
The larger portion of the preliminary plans for this research were 
made in conference with our colleague, Dr. Thorne M. Carpenter, who 
had expected to be actively associated with this work. An unfor- 
tunate typhoid fever infection in the early fall made it necessary for 
him to withdraw completely from the investigation, although in the 
last few weeks he kindly cooperated in some of the temperature and 
pulse measurements. His absence from the Laboratory was keenly 
felt by all, since we had greatly counted on his counsel and coopera- 
tion. Fortunately, the entire manuscript has had his critical reading. 
REDUCTION OF BODY-WEIGHT OF SUBJECTS. 
In our research on the effect on the metabolism of reducing the body- 
weight by alterations in diet, several plans for reducing the weight of 
the subjects suggested themselves. The total weight reduction was 
tentatively set at 10 per cent in the belief that a 10 per cent loss would 
be of sufficient magnitude to show positively any changes in the metab- 
olism, while a percentage less than this might not be measurable with 
