PULSE-RATE. 425 



February 14 to 19, 1918, records being made of their transition pulse. 

 The curves for these normal subjects appear in figure 101. In these 

 figures the durations of the pulse cycles, calculated in 0.01 seconds, 

 appear as ordinates. The abscissae show the number of pulse cycles. 

 The curves have been drawn so that each plotted point represents the 

 average of two cycles, thus diminishing the small variations present 

 in the normal heart action and producing a smoother curve. The heavy 

 lines X and Y indicate the moment of transition from standing to 

 walking and the reverse. The pulse cycles to the left of X represent 

 the preliminary standing period. Those to the right of X represent the 

 initial walking period. Similarly, the cycles to the left of Y are for 

 walking and those to the right of Y are for standing. Between these 

 two transition curves, there has also been inserted a short curve repre- 

 senting the pulse-rate at the sixth, twelfth, and twenty-fourth minutes 

 of walking. Thus there are shown for each subject (1) the curve for 

 the walking transition following standing; (2) the curve for the standing 

 transition following walking ; and (3) a curve for the pulse-rate at three 

 points, usually after 6, 12, and 24 minutes of walking. The approxi- 

 mate pulse-rate corresponding to the length of pulse cycle is given on 

 the right of the figure. Intervals of approximately 15 seconds are 

 shown by the smaller figures at the bottom of each transition curve. 

 The sixth, twelfth, and twenty-fourth minutes are also indicated on 

 this Hne for the intervening walking curve, but it should be clearly 

 understood that the times between these points, as represented by the 

 abscissae, are not uniform. For instance, with Fis, the time covered 

 by the preliminary standing pulse record was 14.3 seconds. The first 

 twenty cycles of walking lasted 15.4 seconds, while the entire walking 

 portion of this transition record was 59.7 seconds. There is then an 

 interval of slightly over 5 minutes before the pulse-rate for the sixth 

 minute, and intervals of 6 and 12 minutes between the next two 

 points. After the twenty-fourth minute, there is an elapsed period of 

 approximately 2 minutes before standing began at Y. The ten pulse 

 cycles of walking preceding the standing lasted 9.2 seconds, while the 

 standing record was 28.6 seconds. 



TRANSITION PULSE, SQUAD B. 



It is hardly necessary to analyze each individual curve shown in the 

 succeeding figures. The chief points of resemblance and difference can 

 be brought out by considering a few curves from each group. In the 

 pulse of Fis shown in figure 95, the average length of the first two 

 pulse cycles noted was 1.16 seconds. The average of the next two 

 pulse cycles was 1.10 seconds, after which the duration changed to 

 1.22 seconds for the average of the fifth and sixth cycles. From this 

 point the duration of the pulse cycles shortened, and at the transition, 

 X, the length was 0.99 second. The shortening of the duration of the 



