PHYSIOLOGICAL CHANGES IN TRANSITION. 287 



The values for the oxygen consumption during standing are measured 

 in minutes from the kymograph record during 3 or more of the 5 or 6 

 minutes preceding the tune of transition to walking. These unre- 

 duced values for the oxygen consumption range somewhat about an 

 average of 300 c. c. per minute. On March 16, especially in the 

 first, second, and fourth periods, the respiration was uneven and the 

 measurement of the kymograph curve was difficult. 



During the first 30 seconds of walking, the tracings were usually too 

 irregular to determine the rate of oxygen consumption, but in the second 

 half-minute we find the oxygen consumption was in almost every in- 

 stance over 1,400 c. c., or from four to five times the standing require- 

 ment. As a rule, in the third half-minute the oxygen consumption 

 increased an additional 300 to 500 c. c., or a further increase of about 

 one-quarter of that which occurred in the second half-minute. The 

 values for the fourth half-minute are approximately of the same charac- 

 ter as those in the third half-minute, but with the increases over the 

 preceding half-minute somewhat diminished. By the fifth half-min- 

 ute, and certainly by the sixth half-minute (from 2| to 3 minutes after 

 the walking began), the oxygen consumption apparently reached a 

 point indicating that the rate of consumption was commensurate with 

 the body requirements for the work in hand. Beyond this point the 

 rate of oxygen consumption remained essentially uniform for the re- 

 mainder of the experimental period, irrespective of the amount of 

 work being performed. 



RESPIRATORY CHANGES IN TRANSITION FROM GRADE WALKING TO STANDING. 



The respiratory changes during the transition from grade walking 

 to standing were also measured in like manner as those for the transi- 

 tion from standing to grade walking. (See fig. 38, p. 278.) The values 

 for the respiration-rate and pulmonary ventilation are given in tables 



83 and 84 and for the rate of oxygen consumption in table 85. 



In eight of these experiments the transition was measured during the 

 final standing period after the subject had been walking during the 

 preceding periods of the forenoon. The walking stopped simulta- 

 neously with the beginning of the period and the respiration-rate 

 and pulmonary ventilation were measured and compared with the 

 average values for the preceding walking periods. (See table 83.) 

 On only three of these days was an attempt made to estimate the oxy- 

 gen consumption, and then only with the subject standing. 



On March 10 and 11, in addition to the preliminary walking, the 

 subject walked 3 or 4 minutes of the period and then stood. Observa- 

 tions for four periods were obtained on these two days. During these 

 periods, the respiration, ventilation, and oxygen consumption were 

 determined for both the walking and standing portions. (See tables 



84 and 85.) The subject rested in the intervals between periods and 



