PULSE-RATE. 429 



Liv (figure 96) is the only subject whose pulse cycles do not show a 

 marked lengthening in the duration following the first stimulus of 

 walking. The sixth cycle lengthened slightly to 1.10 seconds, but the 

 curve is in marked contrast to the others and with minor variations 

 is that of a constantly shortening pulse cycle. The immediate length- 

 ening of the cycle at the end of walking continued only through the 

 eighth beat, when it was again followed by a marked shortening period 

 for 6 cycles, after which it continued with an irregularly lengthening 

 interval. 



The curve for Tho (figure 97) is in the main like the others, but as 

 only 29.7 seconds of the walking transition was secured, it is incom- 

 plete. An incipient lengthening of the cycle took place at the sixth 

 beat, but the marked change did not occur until the fourteenth beat, 

 when the duration changed from 0.96 to 1.13 seconds by the twenty- 

 fourth cycle. At that point the quickening of the pulse apparently 

 began, but the record here is incomplete. The pulse cycle was fairly 

 uniform for the 9 cycles at the end of walking, with a duration of 1.18 

 seconds. This is approximately the duration of the original standing 

 cycle. The cycle reached its maximum length of 1.39 seconds at the 

 tenth beat, after which it shortened to 1.23 seconds at the twentieth 

 beat. 



The general picture which these figures for Squad B present is that 

 of a rising curve — i. e., a shortening pulse cycle — beginning from 4 to 

 8 cycles before the transition to walking and continuing through the 

 transition for a period rarely exceeding 12 cycles, and often not over 

 4 cycles. The curve then descends, reaching its maximum depression 

 at or near the twentieth cycle, from which a second ascending curve 

 begins. 



At the final transition to standing less regularity is seen, but in 

 general it may be said that the response by the heart is prompt, and 

 the curve descends to a minimum at about the tenth cycle, after which 

 there is a more or less pronounced rise, persisting for a few cycles, and 

 then a tendency to fall slightly. 



The initial rise while the subject was still standing before walking 

 is accounted for from the routine of the experiment. Previous to the 

 taking of the photographic record the subject had been standing 

 quietly on the treadmill for some time. At a certain moment the 

 assistant gave audible warning to the other assistants that he would 

 start the mill in 15 seconds. This warning could be heard by the 

 subject in the chamber, and a psychically stimulated pulse-rate fol- 

 lowed in anticipation of the beginning of walking. The acceleration 

 due to the anticipation of the starting of the treadmill makes it difficult 

 to compare the pulse-cycle durations of the period of standing pre- 

 liminary to walking with the pulse-cycle durations during walking. 

 Some of the curves indicate that this psychological disturbance is 



