300 



METABOLISM DURING WALKING. 



versed numbering of the groups of cycles, shows similar irregularities 

 and marked lengthening in the duration of the cycles previous to the 

 beginning of walking at X. The rise in the curve subsequent to the 

 beginning of walking was decided and regular for 20 cycles, or approxi- 

 mately 15 seconds. Thereafter the rise was more gradual, and after 

 1 minute of walking the rate was fairly uniform at 0.45 second. Curve 

 C is a record taken after the walking had been in progress for 2 minutes 

 and-covers a period of approximately 1 ^ minutes. During most of this 

 time the pulse-cycle was between 0.5 and 0.4 second in duration, 

 shortening slightly with the time and ending at 0.4 second. 



10 20 30 40 20 

 PULSE CYCLES 



60 70 80 90 100 110 120 130 



FIG. 40. Duration of pulse-cycles of E. D. B. in grade-walking experiment of Feb. 28, 1916, 



as indicated by averages of 2 pulse-cycles, measured individually. 



A, standing; B, transition standing to walking; beginning of walking at X; C, D, and E, walking 

 after 2, 26, and 30 minutes, respectively, of continuous walking. Curves D and E with 

 lengthened record of time-interval. The time required for groups of cycles, varying in 

 number, is indicated by small figures and inclusion marks below each curve. 



After the subject had been walking continuously 26 minutes, a 

 record was taken in which the photographic paper was put through 

 the camera at a rate of approximately 5 cm. a second, which produced 

 a space interval between the pulse-cycles of from 12 to 15 mm. This 

 permitted measurements with a greater degree of accuracy, the results 

 being given in curves D and E. As in the other curves, the points 

 represent the averages of 2 cycles. The durations of the pulse-cycles 



