From these values it is seen that Sne was able to move 1 kg. of body-weight 1 meter with the least output of energy (0.479 gram-calorie), while Kim expended the most at 0.745 gram-calorie. This extreme value of 0.745 gram-calorie found for Kim is open to suspicion, for such a heat output is not approached by any of the other subjects during these tests or by any of the normal men shown in table 139. Excluding the value of 0.745 gram-calorie, the average heat output per horizontal kilogrammeter is 0.597 gram-calorie for the remaining 11 men of the squad which is used for future comparisons.

This average figure may also be compared with the values found with 8 other subjects1 studied in this Laboratory which are given in table 139. There is considerable diversity in this table in the rate of walking, and it has not been possible to find exact data for comparison. The apparatus used was the universal respiration apparatus with mouthpiece and nose-clip, so that differences in technique between the two series may be expected to influence the results in some degree. These figures show an average cost per horizontal kilogrammeter of 0.535 gram-calorie. Benedict and Murschhauser1 report values obtained for 2 normal subjects (their Subject I and Subject II) of 0.507 and 0.493 gram-calorie, and also give an average figure of 0.550 gram-calorie computed from a summary of the work of Zuntz, Durig, Brezina, and others.2 The average value of 0.597 gram-calorie for the 11 men of Squad B is somewhat higher than the values found by the other methods, though the variations are not on the whole any greater. Since such striking prominence is given in table 138 to the individual coefficient per horizontal kilogrammeter, it must be emphasized that these represent determinations upon one subject for one period in the day and hence should not be directly compared to the average values given in table 139, which represent in all cases average values of from 3 to 13 periods. Hence attention is called to the differences in values found in table 139 for the series of normal individuals. It is there seen that in the entire series the lowest average found was 0.458 and the highest 0.627. The lowest average, 0.458, is 0.021 lower than the lowest found with any member of Squad B, i. e., 0.479. The highest average for the normal individuals was 0.627 which is exceeded in table 138 by members of Squad B in five instances, How, Ham, Kim, McM, and Tho. The average for the entire squad, 0.597, is clearly somewhat higher than not only the average found with the normals, namely, 0.535, but likewise the three sets of averages reported in earlier publications. The values found for Squad B in table 138 are to be used primarily for comparative purposes with another set determined on the same individuals by exactly the same technique after 20 days of reduced diet. It is to be remembered that we have here with this apparatus but 12 individual experiments with 12 different men. The fact that their average value is somewhat higher than that found by another technique with 8 other subjects, and which represented a large number of series, is not to be given undue prominence.

1 Detailed data to appear in a later publication.

Table 139. - Average Metabolism Of Normal Men For Horizontal Walking

1 Benedict and Murschhauser, Carnegie Inst. Wash. Pub. No. 231, 1915, pp. 77 and 82. 2 Ibid., p. 28.

Walking Experiments With Reduced Diet, Squad B

Two days after the experiments on January 6 were made with Squad B the reduction in diet previously discussed was begun and continued for 20 days. On January 28, the last day of restricted diet, a second series of tests was made. These duplicated in every respect those of January 6, with the exception that McM had been obliged to leave the squad and Lon had returned.

The metabolism of the men as measured while standing, preliminary to walking, appears in table 136. From tables 138 and 140, we find that the average heat production per minute of the 12 subjects fell from 1.37 calories on January 6 to 1.10 calories on January 28, or a decrease in the heat output from the body of 19.7 per cent. The averages are unaffected by including the values found with McM and Lon.

A summary of the gaseous metabolism and computed heat output for the walking experiments of January 28 is given in table 140. Here, also, the average rate of walking remained constant in all experiments, again attesting to the uniformity in action of the mill. The respiratory quotients, except that for Wil, which is relatively high, are fairly uniform and are of the usual value. The total heat output bears a reasonable relationship to the body-weight of the subject. Special attention is called to the values for the total heat required for walking 10 km., i. e., the average day's walking performance. The average for the entire squad is 533 calories. These values in the last column may be compared to the corresponding values on January 6 for normal diet. The total heat increase above standing is of special significance, but attention must also be called to the heat requirement for transporting 1 kg. 1 meter (column k). Here the values range from 0.493 with Tho to a maximum of 0.652 with Har. The average value is 0.562. The range in values in this series of experiments is very much less than that in the earlier series, in which it will be recalled that the values ranged from 0.479 to 0.745. A comparison of the average values may be made best in connection with the comparison of all the several factors.