94 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



been taken. Here, 1\ hours after food, the metabolism was 629 

 calories, rising an hour later to 647 calories, thereafter falling continu- 

 ously until two minimum periods of 545 and 555 calories are found at 

 9 and 11 hours, respectively, after the food had been taken. If we 

 consider the absolute minimum of 545 calories as basal, then the 647 

 calories, or the maximum heat production, represents an increase of 

 102 calories, or about 20 per cent, due to the influence of food. But 

 this increase is relatively soon after feeding. The pulse-rate likewise 

 shows a distinct tendency to fall off after the first rise due to the taking 

 of food. The average value of 550 calories, which may be taken as 

 the basal value, was determined, roughly speaking, 10 hours after the 

 last meal. 



An examination of the chart for No. 171 (see fig. 16, page 124) shows 

 that at the age of 13| months there is a decided break in the line for 

 the total calories, indicating a fairly low value at that time. The 

 period of observation is considerably longer than that for most of the 

 children in the series. It is therefore quite likely that, had the experi- 

 ment been shorter, the point would more closely correspond to the 

 general trend of the curve. But great stress should not be laid upon 

 individual variations from day to day or from period to period. 



On April 17-18, 1916, a long experiment was made with the infant 

 No. 123, in which the child took food containing but 60 calories of 

 energy* The metabolism was thereafter measured continuously for 

 over 9 hours. While the absolute minimum value of 312 calories was 

 found in the last period, the values for the last 2 hours indicate relative 

 constancy. The maximum of 378 calories, which occurred 2 hours and 

 9 minutes after food, is equivalent to an increase of 66 calories above 

 the minimum, or, roughly speaking, 20 per cent. The pulse-rate shows 

 a general tendency to decrease after the maximum metabolism is 

 reached, although the minimum pulse-rate is not coincidental with the 

 minimum metabolism. 



The series of observations with No. 131 continued for 9| hours after 

 food. The amount of food taken was insignificant in quantity and 

 energy content, and the minimum value actually appeared about 4| 

 hours afterwards. The maximum value (391 calories) was found 9| 

 hours after food, or some 5 hours after the minimum value appeared. 

 The great increase in the pulse-rate is wholly inexplicable, for the 

 kymograph records indicate activities of but I and II, and the subject 

 was presumably asleep. We have no explanation for these unusual 

 figures. 



With the other children, shorter observations were the rule after 

 food. With No. 127, on April 20-21, 1916, five feedings were given, 

 the observations after the first feeding continuing without break for 

 5 hours and 31 minutes. The absolute minimum of 255 calories was 

 found about 5 hours after food. As the maximum value, which was 



