132 



GASEOUS METABOLISM OF INFANTS. 



Observation with J. V., April 22, 1913. 

 Inasmuch as the longest series of experiments with any infant was that made 

 with J. V., and this infant was very small and weak, a second curve is shown, 

 which was obtained on April 22, 1913 (see figure 44). The body-weight at 

 this time was 2.93 kilograms. But one period can be characterized as activity 

 II, i. e., that between 3 h 55 ra p. m. and 4 h 15 m p. m. The difficulties incidental 



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J.V. 

 APRIL 22. 1913 



Fig. 44. Kymograph curve for J. V., April 22, 1913. 



to differentiating sharply between the several classifications of activity may 

 here be pointed out, in that during the period from 4 h 41 m p. m. to 5 h 9 m p. m., 

 in which the activity is characterized as III, the heat-production was actually 

 a little less than that in the period between 3 h 55 m p. m. and 4 h 15 m p. m., in 

 which the activity was classified as II, while the pulse-rate was exactly the 

 same (see table 25). On the other hand, in the preliminary and first periods, 

 with the activity characterized as V and VI respectively, both the pulse- 

 rate and the heat-production were considerably higher than in the other 



Table 25. — Comparison of the pulse-rate, metabolism, and muscular activity in 

 observation with J. V., April 22, 1913. 



•Preliminary period. 



periods. Furthermore, in comparing these two periods with each other, we 

 see that in the preliminary period when the activity was V and the pulse-rate 

 136, the heat-production was a little higher than that for the first experimental 

 period, notwithstanding the fact that both the pulse-rate and the activity were 

 higher in the latter period. 



Throughout this whole monograph, it is important to note that the use of 

 data obtained in the preliminary periods may lead to error, since the amount 

 of carbon dioxide residual in the chamber may be somewhat less at the end of 

 the period than at the start and the temperature conditions may not be ideal ; 

 hence the determinations as a whole may be less accurate than those of the 

 subsequent periods. Nevertheless, it is interesting to note in this curve the 

 occasional lack of agreement between the muscular activity record, the pulse- 

 rate, and the total heat-production. As a possible explanation of this, we may 



3 40 



