108 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



muscular activity. In this period the carbon-dioxide production was 

 6.78 grams per hour, corresponding to a heat production of 474 calories 

 per 24 hours or 52 calories per kilogram of body-weight. It is unfortu- 

 nate that no other period confirms this low value and that no test was 

 made until December 4, nearly 2 weeks later. On this latter date no 

 values are found so low as the minimum for November 22, although 

 one period gives 505 calories per 24 hours or 53 calories per kilogram 

 of body-weight 1 as compared with 52 calories observed on November 22. 

 It is not unreasonable to consider that these two periods verify each 

 other. 



In analyses of the period values in these experiments, it is evident 

 that verification by similar figures on another day or duplicate periods 

 on the same day are highly desirable for establishing the true minimum 

 metabolism. But this is by no means possible in every day's experi- 

 mentation. Uncontrollable activities of III or more immediately 

 rule out estimates for minimum values. 



Frankly, the pulse-rate does not give invariably so close a correla- 

 tion with the activity and the metabolism as we had expected. Thus, 

 with the low period on November 22, the pulse-rate was 117, while 

 in the most active period it was but 120. The respiratory quotients 

 in the first four observations with this child range from 0.80 to 0.90 

 and are fully in line with the quotients which might be expected from 

 the character of the diet. No abnormalities in the respiratory quo- 

 tients are to be seen in the entire series, save that the low value of 

 0.76 in the last observation on June 14, 1919, is unusual. 



An examination of the figures for the carbon-dioxide production as 

 the observations progressed, giving due regard to the variations in 

 activity, shows that the carbon-dioxide production during periods of 

 minimum activity gradually increased as the age, height, and weight 

 increased. With this child, at least, the minimum or basal metab- 

 olism for any given day is usually marked sharply. 



The only experimental factor which varies in this series of observa- 

 tions, other than that of activity, is the food, as the amount taken, 

 the character of the food, and the time between feeding and the first 

 observation differ more or less on the several days. Theoretically the 

 stimulus to cellular activity and to the metabolism increases with the 

 increase in the amount of food and with the shortening of the interval 

 between the taking of food and the beginning of the observations. 

 Practically, when one attempts to correlate the amounts of food given, 

 its character, and the length of time prior to the observation, it is 

 only with difficulty that clear evidence can be found, of the influence 

 of food upon the basal metabolism. At first sight it would seem that 

 this point is illustrated by the data for January 31, 1917, and those 



1 When the body-weight changes without material change in age, comparisons are best made on 

 the basis of equal units of weight. 



