TENSION-EQUALIZER AND SPIROMETER UNITS. Ill 



show the possible differences which may exist between the respiratory 

 quotient for a man in a chamber perfectly free to breathe naturally and 

 that for a man connected with a respiration apparatus. 



THE TWO TYPES OF THE BENEDICT RESPIRATION APPARATUS (THE TENSION- 

 EQUALIZER UNIT AND THE SPIROMETER UNIT). 



During the later comparison of the bed calorimeter and the tension- 

 equalizer type of the Benedict universal respiration apparatus, a modi- 

 fied form — the spirometer unit 1 — was developed, perfected, and put 

 into use. While the spirometer unit was not employed in the com- 

 parison with the bed calorimeter, it was used in some of the comparisons 

 with other respiration apparatus, and it was therefore considered advis- 

 able to compare the respiratory exchange as determined by both the 

 tension-equalizer unit and the spirometer unit. If the two types of 

 apparatus gave comparable results, it could logically be concluded that 

 results found comparable with either the tension-equalizer unit or the 

 spirometer unit would also be comparable with those obtained with 

 the bed calorimeter. 



Several comparison experiments were accordingly carried out with 

 the two types of this respiration apparatus. The general routine and 

 accessory apparatus were practically the same as in the comparisons 

 of the tension-equalizer unit and the bed calorimeter. The subjects 

 were in the post-absorptive condition and always lay upon a couch; the 

 preliminary period was approximately 30 minutes long, the experi- 

 mental periods usually being 15 minutes in length. As the two types 

 of apparatus were placed side by side, the subject, with couch, could 

 be readily moved from one apparatus to the other without muscular 

 activity on his part. The tension-equalizer unit and the spirometer 

 unit were alternated or used in series, i. e., several periods carried out 

 with one apparatus followed by several periods with the other. Pneu- 

 matic nosepieces were used throughout the comparison. 



The pulse-rate was recorded by means of a Bowles stethoscope, and 

 the respiration-rate with a tambour, pointer, and kymograph attached 

 to a chest pneumograph. Graphic records of the activity were ob- 

 tained with a pneumograph fastened about the hips of the subject and 

 connected with a tambour and kymograph. All of the young men had 

 previously acted as subjects in the comparison experiments with the bed 

 calorimeter and the tension-equalizer unit. Three of these, K. H. A., 

 J. B. T., and J. K. M., were assistants in the Nutrition Laboratory; the 

 others were medical students. The statistics of the 9 comparisons 

 follow. 



^ee p. 34. 



