ZUNTZ-GEPPERT AND BENEDICT METHODS. 129 



ZUNTZ-GEPPERT RESPIRATION APPARATUS AND BENEDICT RESPIRATION APPARATUS 



(SPIROMETER UNIT). 



In addition to the foregoing series of experiments, in which the Zuntz- 

 Geppert respiration apparatus was compared with the tension-equalizer 

 type of the Benedict respiration apparatus, a second series of experi- 

 ments was conducted in which the same apparatus was compared 

 with the spirometer type of the Benedict apparatus. The Zuntz gas- 

 analysis apparatus was not used in this series of experiments, but the 

 samples of air were collected over mercury in a tourniquet apparatus 

 or in gas-samplers of about 300 c.c. capacity, and the analyses were 

 made later with the laboratory form of the Haldane gas-analysis 

 apparatus. As this procedure is not strictly according to the Zuntz- 

 Geppert method, the second series of experiments can not be considered 

 as an actual comparison of the Zuntz-Geppert apparatus and the spir- 

 ometer unit. The essential principle of the Zuntz-Geppert method of 

 the measurement of the expired air and the method of aliquot sampling 

 for analysis was, however, adhered to in this comparison. 



The preliminary ventilation in the experiments with the Zuntz- 

 Geppert apparatus was usually obtained for several minutes preceding 

 the experimental period, and observations are given for the preceding 

 5 minutes when they were secured. As a rule, the pneumatic nose- 

 pieces were used with the spirometer unit and the ordinary form of 

 rubber mouthpiece with the Zuntz-Geppert apparatus. The pulse- 

 rate was, as in previous comparisons, obtained with the Bowles stetho- 

 scope, in nearly all cases 5 counts being made in a 15-minute period. 

 The chest pneumograph was ordinarily used for obtaining the respira- 

 tion-rate, especially in the experiments with the Zuntz-Geppert appa- 

 ratus. With the spirometer unit it was obtained by means of the 

 recording device attached to the drum of the spirometer, but in some 

 cases the pneumograph was also used. In practically all of the experi- 

 ments a record of the activity was secured from a pneumograph placed 

 about the hips of the subject, so that slight movements of the body or 

 of the legs would be recorded. The subjects used in this comparison 

 series differ somewhat from those employed in the earlier comparisons, 

 the maj ority being untrained men. They were mostly medical students 

 who were obtainable in the early morning before attending lectures. 

 The statistics and results of the 22 experiments are given in the follow- 

 ing pages. In addition to the data given in the earlier comparison, 

 the average barometric pressure and the average temperature of the air 

 in the apparatus are recorded. 



STATISTICS OF EXPERIMENTS. 



H. F. T., January 18, 1912. — Spirometer unit, 4 periods; Zuntz-Geppert 

 apparatus, 2 periods; first three and last periods, spirometer unit; fourth and 

 fifth periods, Zuntz-Geppert apparatus. Pneumatic nosepieces used with 

 both apparatus. No preliminary ventilation records were taken with the 



