TISSOT AND BENEDICT METHODS. 145 



Usually the apparatus were alternated in each experiment, the appa- 

 ratus first used varying. In two experiments the periods with each 

 apparatus were in series. The duration of the periods was, as a rule, 

 approximately 15 minutes, except when the 50-liter spirometer was used, 

 when they were only 10 minutes in length. No special preliminary 

 ventilation was obtained with either apparatus, the periods beginning 

 about 5 minutes after everything was in readiness. 



The pulse-rate was obtained by means of a Bowles stethoscope placed 

 over the heart of the subject. Usually five separate counts, each a full 

 minute in duration, were made during a 15-minute period. A graphic 

 record of the respiration was secured with a pneumograph placed about 

 the lower chest of the subject and connected with a tambour and kymo- 

 graph. The external muscular activity of the subject was controlled 

 with a pneumograph placed about the hips. Only two subjects were 

 used for this series of experiments, H. F. T. and K. H. A., all but one 

 of the experiments being made with H. F. T. Both were young men 

 who were accustomed to respiration experiments of this type. The 

 statistics of the 10 experiments are given in the following pages. In 

 addition to the data usually recorded, the average barometric pressure 

 and the average temperature of the air in the apparatus are given. 



STATISTICS OF EXPERIMENTS. 



H. F. T., August 8, 1911. — Tension-equalizer unit, 4 periods; Tissot spiro- 

 meter, 3 periods; first two periods with tension-equalizer unit; apparatus 

 alternated thereafter. Pneumatic nosepieces; 50-liter spirometer. Prelimi- 

 nary ventilation for 10 to 12 minutes in the periods with the Tissot apparatus. 

 Pulse-rate for the most part uniform in all of the periods. Respiration in the 

 various periods similar and fairly regular. This subject had a tendency to 

 irregularity in length of individual respirations and some respirations were 

 longer than others, with pauses at the end of an expiration. Average baro- 

 metric pressure 760.4 mm. ; average temperature of air in apparatus 24.4° C. 



H. F. T., August 9, 1911. — Tissot apparatus, 4 periods; tension-equalizer 

 unit, 3 periods; periods with each apparatus in series; preliminary period, 

 7 minutes. 50-liter spirometer. The nosepieces were not removed during the 

 entire series with the Tissot apparatus. Pulse-rate very uniform. Respira- 

 tion in the first three periods with the Tissot apparatus somewhat irregular, 

 with many periodic pauses; with the tension-equalizer unit, somewhat more 

 regular. Average barometric pressure, 759.2 mm.; average temperature of 

 air in apparatus, 23.9° C. 



H. F. T., August 28, 1911. — Tension-equalizer unit, 4 periods; Tissot appa- 

 ratus, 3 periods; first two and last two periods with tension-equalizer unit. 

 Pneumatic nosepieces, both types of apparatus; with Tissot apparatus, 50- 

 liter spirometer; nosepieces inserted about 10 minutes before each period 

 began. Pulse- and respiration-rates fairly regular. Average barometric 

 pressure, 758.9 mm. ; average temperature of air in apparatus, 19.2° C. 



H. F. T., August 26, 1911. — Tissot apparatus, 5 periods; tension-equalizer 

 apparatus, 4 periods; apparatus alternated. With Tissot apparatus, 50-liter 

 spirometer; nosepieces inserted 10 minutes before each period began. Pulse- 

 rate uniform. Respiration-rate essentially uniform in all periods. Average 



