GENERAL ROUTINE OF THE EXPERIMENTS. 45 



for approximately 15 minutes. At the end of a normal expiration the 

 valve was again turned and the experiment was completed. During 

 the entire experiment oxygen was admitted regularly from a cylinder, 

 the gas being passed through a carefully calibrated Bohr gas-meter 

 immersed in water. At the conclusion of the experiment the ventila- 

 tion was continued for a few minutes to insure the thorough sweeping 

 out of all the carbon dioxide; finally the tension-equalizer was filled 

 with oxygen to the same tension that existed at the beginning of the 

 experiment. 



Owing to the greatly increased carbon-dioxide production during 

 severe muscular work, the ventilating current was so adjusted that 

 the ventilating pump would cause 80 to 90 liters of air to pass by the 

 mouth of the subject per minute, thus minimizing the danger of the 

 rebreathing of the air. Furthermore, by means of the supplementary 

 valve M (see fig. 2, page 34), the dead space in the rubber tube leading 

 from the mouthpiece to the main air-pipe was wholly eliminated, for 

 when the valve N had been turned after the beginning of the experi- 

 ment, all of the air passed immediately by the mouthpiece. While 

 this deflection of the air-current was unnecessary in the experiments 

 with the subject standing, nevertheless it was also used in these experi- 

 ments in order that the procedure might be the same in both series. 



Since it is important to note whether or not the subject remained in 

 essentially the same degree of muscular repose throughout the standing 

 experiments, a graphic record was obtained of the degree of movement 

 by connecting the subject with a cord attached to a movable pointer 

 traveling over a smoked-paper kymograph. In an ideal experiment 

 the course of the pointer would be a straight line. While it was impos- 

 sible for the subject to remain as perfectly quiet as he would when lying 

 upon a comfortable couch, nevertheless the regularity and constancy 

 of the muscular repose of the subject from experiment to experiment 

 was, to say the least, very striking. We are therefore safe in assuming 

 that in practically no experiment were the irregularities in the metabo- 

 lism for the standing position attributable to changes in the degree 

 of muscular repose of the individual, except in those tests in which 

 special positions while standing were assumed, such as the position of 

 "attention." 



SITTING EXPERIMENTS. 



A few sitting experiments were also made with one of the subjects. 

 These were not used as a base-line, but are recorded simply to show that 

 an endeavor was made to secure the best possible base-line for deduc- 

 tion from the total metabolism obtained during walking. The incre- 

 ment in the metabolism for the sitting position was unfortunately not 

 studied with sufficient sharpness to make a definite conclusion possible. 



