In connection with the walking experiments of January 6 and 28 and February 3, it was planned to secure the pulse records photographically with the subject sitting and standing preliminary to walking, at the first, sixth, twelfth, and twenty-fourth minutes of walking; and finally a few wrist counts during the 10 minutes following walking. The difficulties in this program lay in the overlapping of the experiments, due to unavoidable delays at one point or another in the routine, to an occasional poor contact of the body electrodes, or to a defective grounding of the subject. These difficulties made it impossible to get a complete record in every instance; those obtained are given in tables 98, 99, and 100. The pulse-rates at the sixth, twelfth, and twenty-fourth minutes of walking are also shown for January 28 and February 3 in figures 95 to 100.

If an attempt is made to use only averages which include a complete series for each man, we find that there are too few for a satisfactory comparison; the average pulse-rates per minute for each squad are therefore for such records as are available in each series of observations. The comparisons are made from these averages, which in some cases consist of the entire squad of 12 subjects, while in others a smaller number are included.

Table 98 gives the records of January 6 with Squad B, normal. If the sitting pulse records are compared with those taken the evening previous in connection with the series of psychological tests (see p. 403), we find in the main an agreement that is as close as could be expected with conditions so different. But the pulse-rates of Sch and Sne (92 and 97) are so high and so much higher than the other sitting records that it indicates the presence of an unusual stimulus. This is the more apparent when the standing pulse is considered, for whereas all the other subjects show an increase, these two men show a drop of 24 and 28 beats, respectively. The average sitting pulse for the group is therefore taken as 72 beats and does not include these two high pulse-rates of Sch and Sne.

The records of the standing pulse were taken after the subjects had been standing 10 minutes. In a few cases on this date the subjects stood on the treadmill, while others stood in an adjoining room. The average standing pulse includes both locations, and for the 11 subjects is 79 beats, which is an increase over the average sitting pulse for 8 subjects of 10.0 per cent.

An inspection of this table shows that in most cases by the end of one minute of walking, the pulse-rate increased over that for standing, but that the rate for Fis, Ham, and Liv was slightly lower. The average for the 12 men is 88. This is an increase of 22 per cent over the average sitting pulse-rate and of 11 per cent over the average standing rate. By the end of 6 minutes of walking the pulse-rate shows in 8 cases a decrease from the rate after one minute of walking, ranging from a maximum of 8 beats for Har and Wil to 2 beats for Sne and Tho; of the remaining 4 subjects, Liv's pulse increased 3 beats and Kim's and Ham's 1 beat each; McM's pulse showed no change; the average is 85 beats or an increase of 8 per cent over the standing pulse. At the twelfth minute the average pulse-rate was like that of the sixth minute and by the end of 24 minutes it was but 1 beat per minute higher than at the end of the first minute of walking.

Table 98. - Pulse-Rate Preceding, During, And Following Walking In The Treadmill Chamber And Percentage Change From The Standing Rate - Squad B, Normal, January 6, 1918

1Omitting Sch and Sne.

The sitting pulse following walking, which was taken at the wrist, had an average of 66 beat9 by the second minute; this was below the sitting pulse taken photographically before walking. It was still below the initial pulse after 7 minutes of sitting, although there was a slight rise to 67 beats. If these pulse-rates were plotted with the rate as ordinates and the time as abscissae, the resultant curves would show a fall between the end of the first and of the sixth minutes, followed by a return at the end of 24 minutes to a rate not differing greatly from that at the end of the first minute. The exact location of the lowest point of the depression which occurs between the first and sixth minutes is not evident from the data in the table as no records were taken on this day between these two points. Some indication of this may be seen from figures 95, 96, and 97, in which a curve has been inserted between the curves of the two transitional pulse records, which shows the relation of the pulse-rates at the sixth, twelfth, and twenty-fourth minutes. It is seen that in the majority of cases the pulse-rate is lower at the sixth minute than it was at the end of the transitional period.

The pulse-rates for Squad B on January 28 are given in table 99. On this date an attempt was made to enlarge the pulse data by securing more than one record or observation for the sitting and standing pulse and to obtain records both with the subject standing in an adjoining room as well as standing on the treadmill. The sitting pulse recorded at the start is the average of 2 observations for How, Ham, and Van; 3 for Fis, Sne, and Tho; 4 for Kim; and 5 for Liv. For the period of standing outside the chamber there was 1 observation each for Har, Lon, and Sch; 2 for Tho; 3 for Fis, How, Ham, Sne, and Van; and 4 for Kim. In the observations taken with the subject standing on the treadmill Ham, Sch, Liv, and Wil each have 1, Sne 2, Van 3, Fis 4, and Kim 5.

As described in the section on technique (see p. 130), the pulse records were also increased on this date over those of January 6 by making, with the aid of a stop-watch, a visual count of 20 deflections of the shadow of the string of the galvanometer across the face of the camera at the end of each minute of walking. Since the pulse was photographed for the transition from standing to walking, which continued through the first minute, no photograph was taken for the record after 1 minute of walking, as was done on January 6, but instead a visual count was made.