Squad B was at this time on normal diet; hence the only conclusion that can be drawn is that the respiratory rate of the subjects inside the respiration chamber is practically unaltered by walking during the short period of 24 minutes, and that the carbon-dioxide increment inside the chamber had no measurable effect upon the respiration rate. This is perhaps the most important point to be noted from this particular test and indicates again that this squad is a true control for the subsequent test made with Squad A, as well as the test with Squad B after the men had been put on low diet. Thus it may be fairly assumed that an increment in carbon dioxide may be ruled out as a factor affecting respiration rate - at least the percentage of carbon dioxide with which we deal here.

On January 28 a second series of walking tests was made with Squad B at the Laboratory during which the respiration rate was counted. An examination of the data given in table 110 shows that here again we were particularly unfortunate in not securing a large number of counts before and after walking. Even a larger number of these records were illegible than in the first test and can not be recorded with any degree of accuracy. The 2 subjects with whom prewalking values were obtained showed an increment due to walking. Of particular significance is the apparent increment in the case of Sne, who went from 18 counts to 26 during the first minute of walking. After the first minute the rate rose to 29 per minute. The prewalking value of 18 was based upon a count of only three respiratory cycles and is thus somewhat uncertain. Consequently the evidence is by no means clear from these data that under these conditions walking results in an increased respiration rate. With five of our subjects we have records for standing after walking. In all five cases we find a material drop in respiration rate following the last record obtained for the walking. This fall is as much as 7 respirations in the case of Fis and with the other men ranges from 1 to 6.

From the beginning to the end of walking there is an increase with Fis of 5 respirations; with Ham 6; and with Kim 1. With all other subjects except Sne, the records are incomplete, but the evidence points to a tendency for a slight increase in the respiration rate as the walking continued. This, coupled with the striking fall previously noted in practically all cases after the walking ceased, may be an actual indication of an effect of low diet upon the respiration rate.

The absence of respiratory studies with Squad A under normal conditions is much to be regretted. Although we obtained a larger number of prewalking records than with Squad B, they are in large part based upon but few respiratory cycles. Thus with Pea, Pec, and Tom the count is based on 3 cycles each. We did obtain, however, a fairly good record in all cases of standing after walking.

In only 5 cases could the immediate transition from standing to walking be considered, but in all these there is an increase, i e., 4 with Moy and Pec, 3 with Tom, and 2 with Gul and Vea. Continued walking produced a slight increase with all of the subjects. In general the counts subsequent to the sixth minute were remarkably uniform. There was, therefore, with this squad a tendency for continued walking to produce a slight increase in the respiratory rate. This is in accordance with the general evidence presented by Squad B. That this can hardly be due to the increment in carbon dioxide is, we believe, proved by the experience with Squad B on January 6, prior to reduced diet. It may thus be taken as probable that during walking with low diet there is a slight tendency for the respiratory rate to increase somewhat. After the cessation of walking, and when the subject was still standing upon the treadmill, the respiration counts in practically every instance decreased, and noticeably so, the most striking instance being that of Moy, whose respiration rate fell from 23 to 13. In a certain sense this evidence substantiates the other evidence of the experimental data for the increase from standing to walking, since the reverse from walking to standing produced a fall in the respiratory rhythm. The general tendency towards constancy in respiration rate after the first 6 minutes of walking would imply that this transition takes place in the early part of walking and that the slightly faster rate is maintained fairly uniform throughout the rest of the time of walking. The uniformity in respiration rate after walking is very clearly shown by the numerous records obtained for Gul and Vea whose respiration rates were counted practically every 2 minutes throughout the test, the rate remaining for the most part extraordinarily constant.