104 METABOLISM DURING WALKING. 



With H. R. R. the ventilation per minute ranged from 12.1 liters for 

 the first period on March 20 to 6.5 liters for the third period on April 17. 

 The average for the day ranged from 1 1.7 liters on March 20 to 6.7 liters 

 on April 17. This wide variation is undoubtedly due to a psychical 

 disturbance on March 20, when H. R. R. took his first test. Pulmonary 

 ventilation may not be without value in estimating the mental re- 

 pose of a subject. In this connection we should also note the other fac- 

 tors measured, such as pulse-rate and oxygen consumption, these being 

 higher than on subsequent days. This day's results have been excluded 

 from the average, although there is every reason to believe that they 

 represent the pulmonary ventilation at the tune of the experiment. 

 The average ventilation of the lungs with this subject for the entire 

 series of experiments is 8.5 liters per minute, if March 20 is included, 

 and 7.0 liters without this day. The ventilation in the first period of 

 each day is larger than the subsequent periods and the daily averages 

 decreased as the experimenting continued. 



The pulmonary ventilation of T. H. H. ranged from 5.0 to 7.5 liters 

 per minute, with an average of 6.5 liters per minute for the three days. 

 No tendency toward a uniform change in the ventilation from day to 

 day or from period to period is apparent and his ventilation is, on the 

 whole, fairly uniform. 



The experiments with W. K. extended from February to June, 1915. 

 The lowest pulmonary ventilation during this time appeared in the 

 first period on March 11, with a value of 5.5 liters per minute, and the 

 greatest lung ventilation per minute was in the second period on both 

 June 2 and 3, i. e., 10.7 liters. The lowest daily average was 5.7 liters 

 on March 17 and the greatest 10.6 liters on June 3. When we examine 

 this series of figures, it is noted that the ventilation on March 18 

 and that on the dates subsequent to June 1 show marked increases. 

 On March 18 the by-pass (see B, fig. 1, p. 19), deflecting the circulating 

 air-current nearer to the mouthpiece, was inadvertently not turned, 

 thus adding somewhat to the dead-space of the apparatus. It is 

 probably due to this fact that the ventilation was increased from an 

 average of 5.7 liters on the previous day to 9.0 liters per minute on 

 March 18. The by-pass was installed in anticipation of a greater 

 demand for ventilation during exercise and was not considered so 

 essential for the standing experiments. As further evidence of the 

 importance of its use, we have the experiments of June 2 to 14, in 

 which the by-pass was purposely not used, these showing that the 

 ventilation of the lungs is again very much higher. The average ven- 

 tilation of the lungs of 6.5 liters for W. K. does not, therefore, include 

 the data for March 18 and the observations from June 2 to June 14, 

 when the by-pass was not used. If we omit these days from the dis- 

 cussion, we find that the daily average ventilation of W. K. ranged 

 from 5.7 liters (the average for March 17) to 7.4 liters (the average for 



