472 VITALITY AND EFFICIENCY WITH EESTRICTED DIET. 



shown that such graphic records are possible, but since they were not 

 obtained in this research, we must rely solely upon the pictures given 

 by the pneumograph about the chest. It is impracticable to reproduce 

 here the many pneumograph records obtained ■ in connection with 

 these experiments. Careful inspection of the records, however, shows 

 no obvious alteration in the character of the respiration. There is 

 no tendency towards apnoea or dyspnea, nor, so far as the pneumo- 

 graph tracings indicate, any alteration in the character or type of 

 respiration. 



AVERAGE RESPIRATION RATE. 



Since the reduced diet had but a slight effect upon the respiration 

 rate, the fact that the average rate with these men was perceptibly 

 lower than that ascribed to normal subjects of their age^ has no special 

 significance other than to indicate that in all probability the men were 

 well trained, were very little disturbed by the experimenting, and had 

 fullest confidence in the observers. The average respiration rate, 

 even before the reduced diet began, was not far from 14 per minute, 

 a rate which agrees with that found in this Laboratory for men studied 

 under the same normal conditions in an extensive comparison of 

 respiration apparatus, i. e., 14.4 per minute.^ Subsequent discussion 

 will show that the amount of carbon dioxide to be removed per minute 

 by the ventilating current of air passing through the lungs was lowered 

 nearly one-third as a result of the experimental conditions, and it may 

 at first sight seem rather significant that the respiration rate was not 

 lowered more than 1 or at most 2 respirations per minute with the 

 average subject. 



The respiration rate of the man who fasted 31 days^ had a distinct 

 tendency to rise during the prolonged period of fast. The only other 

 data we have which are at all comparable are those reported by Loewy 

 and Zuntz.^ The extraordinarily low respiration rate of Zuntz, which 

 averaged 5.4 respirations per minute in 5 experimental periods on three 

 different days, can be compared with his respiration rate as noted in 

 earlier experiments. A careful examination of these experiments 

 shows that there was a tendency for his respiration rate prior to the 

 war to be perceptibly above 7, although occasional instances of 5.5 are 

 noted. The average respiration rate reported for Loewy during the war 

 of 10.6 per minute is perceptibly lower than most of those noted with 

 our subjects, and, indeed, than the occasional ante-bellum rates for 

 Loewy found in his earlier experiments. It is fairly clear that in all 

 cases, including not only our experiments in this research but those of 



^ See Quetelet, Tigerstedt's Lehrbuch der Physiologie des Menschen, Leipsic, 1913, 1, 7th 



ed., p. 451. 

 ' Carpenter, Carnegie Inst. Wash. Pub. No. 216, 1915; also Carpenter, Proc. Nat. Acad. Sci., 



1915, 1, p. 602. 

 3 Benedict, Carnegie Inst. Wash. Pub. No. 203, 1915, p. 163. 

 * Loewy and Zuntz, Berl. klin. Wochenschr., 1916, 53, pp. 826 and 828. 



