To have such a study of direct practical value, these men must be living normal lives and carrying out their regular activities in the community. Furthermore, they should be of normal weight, rather than obese, to avoid introducing the pathological factor of obesity. In Germany there was at first a somewhat acute period of loss in weight, caused by the sudden stringency in food materials and the inability of the people as a whole to adjust themselves rapidly to the lowered food intake. There was then a period in which the redistribution of food made it possible to hold the body-weight at the lower level. Our study with the group of normal men was therefore made along two definite lines, i. e., to determine the physiological effect of a pronounced reduction in diet under the following conditions:

(a) During the period of loss in weight when the energy of the diet would be supplemented to a considerable extent by drafts upon body material.

(6) During the period of subsequent feeding with a diet selected to maintain the body in equilibrium at the lower body-weight.

During such weight reduction previous experience with fasting men had shown that there would be in all probability a loss in nitrogen, certainly a loss in body-fat, and probably a somewhat lower heat output. Hence it was recognized that the following special records should be made:

First, the total caloric intake of each individual should be obtained, both during the period of loss in weight and especially during the period of maintenance at the lower body-weight.

Second, the total changes in body nitrogen should be determined by establishing 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 fluctuations 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 contributions 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. Thome M. Carpenter, who had expected to be actively associated with this work. An unfortunate 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 cooperation. Fortunately, the entire manuscript has had his critical reading.