The basal metabolism was measured individually in Springfield by two forms of respiration apparatus: First, a respiratory-valve apparatus employing a mask, Tissot valves, and a carefully calibrated spirometer, with Haldane gas-analysis apparatus for the analysis of the expired air (a combination highly recommended by Dr. T. M. Carpenter); and second, a portable respiration apparatus of new design. These measurements were made only with the men in Squad A and with Ham, one of the men in Squad B. Finally, the metabolism measurements in the group respiration chamber in Boston were also practically basal. These group measurements were made with both Squads A and B.

The values obtained with the respiratory-valve apparatus are of the greater significance, particularly for the normal period, for several reasons. In the first place, the apparatus had long been in use and thus was thoroughly tested. The technique had also been carefully developed. The portable respiration apparatus, while thoroughly tested on specially trained subjects, had never been used to any extent on untrained subjects. Hence, during the first few days of the experiment, the portable respiration apparatus was practically an untried instrument, and the data obtained with it can not have the scientific value of those obtained on the respiratory-valve apparatus. Our discussion of the results, therefore, especially of the basal metabolism prior to diet restriction, must deal more particularly with the values found with the respiratory-valve apparatus. In most instances, however, the values for oxygen consumption secured with the portable respiration apparatus have been averaged with the other results. After the first few days the results with both forms of apparatus are considered of equal value.

The chief responsibility for the experimental work with the portable respiration apparatus at Springfield devolved upon Mr. Louis E. Emme8, whose experience with the apparatus led to the betterment of the technique. Mr. Edward L. Fox likewise made a large number of the respiration experiments with this apparatus.

Individual Measurements Of Basal Metabolism, Squad A

The data regarding the normal basal metabolism of Squad A have been recorded in table 113, which gives the body-weight without clothing, height, body-surface as calculated from the height-weight chart, average oxygen consumption per minute, respiratory quotient, and the heat computed from the gaseous metabolism on several bases - i. e., per hour, per 24 hours, per kilogram per 24 hours, and per square meter per 24 hours - and finally, the predicted heat from a series of equations recently published by the Carnegie Institution of Washington.1 The differences, absolute as well as percentile, between the values computed per 24 hours and those predicted are given in the last columns of the table. This table gives results obtained for all the men in Squad A, including Fre, Spe, and Kon; the three last were members of the squad for only a part of the experiment. Additional data are included for one member of Squad B (Ham), whose basal metabolism was determined on several occasions prior to the period of diet restriction in some tests of the apparatus.

An examination of the figures in this table reveals nothing unusual. The average respiratory quotient for Squad A (excluding Bro) is 0.80. The average values for the heat, computed on the various bases are per kilogram per 24 hours, 25.5 calories, and per square meter per 24 hours, 949 calories. The normality of these figures on the whole is indicated by the fact that the average respiratory quotient of 89 men as reported from this Laboratory8 was 0.83 as against 0.80 found in the normal measurements of Squad A. Recently Dr. T. M. Carpenter, Mr. L. E. Emmes, and Miss M. F. Hendry, of the Nutrition Laboratory staff, have measured the metabolism of 17 Harvard Medical School students,1 who showed an average respiratory quotient of 0.82. The heat production per hour per square meter of body-surface found with these 17 men was, on the average, 38.3 calories, a value about 3 per cent less than that found by us with the members of Squad A, i. e., 39.5 calories. A possible explanation of the slightly higher values obtained in our measurements is the fact that our subjects included a relatively large number of men in excellent physical training, and it has previously been shown that athletes have a perceptibly higher basal metabolism than is found with normal non-athletic individuals.2 A comparison between the values found for total heat production per 24 hours and those predicted by the new equations is of special interest. Paying particular attention to the differences, which are shown in the next to the last column of the table, we find that 8 out of the 13 men of Squad A show plus values, that is, have a somewhat higher metabolism than that predicted. The most striking variation from the predicted value is that of Mon, whose total heat production as measured per 24 hours was 1,858 calories as compared with a predicted value of 1,652 calories.

1 Harris and Benedict, Carnegie lost. Wash. Pub. No. 279, 1919.

2 Benedict. Emmes. Roth, and Smith. Journ. Biol. Chem.. 1914. 18. p. 139.