212 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



hour requirement than those previously discussed, although even here 

 the children were not studied during their outdoor or extra-chamber 

 activity. 



In this connection a study may be made of the curves in figures 33 

 and 34 (page 152), in which comparisons are made between the 

 basal metabolism values of our observations and the values 

 obtained in the chamber experiments of foreign investigators just 

 discussed. The curves representing our values for boys from 7 to 

 16 years and for girls from 7 to 14 years are obviously projected for 

 the sake of comparison, as material for the later ages is lacking. The 

 other two curves on the boys' chart correspond to the values computed 

 by Carl Tigerstedt from the earlier chamber experiments (table 38) 

 and the extensive series of observations by Sonden and Tigerstedt on 

 school children ranging in age from 8 to 23 years. On the assumption 

 that the school children would have a varying degree of activity 

 which would be measured with a fair degree of accuracy by the carbon- 

 dioxide production per 2 hours, we selected for the plotting of the 

 Sonden and Tigerstedt curve the more probable minimum carbon- 

 dioxide values at each age, discarding those that were obviously 

 increased by activity. (See table 4, page 10.) Even with this method 

 of eliminating the excessively high carbon-dioxide production, it can 

 be seen that the heat-output obtained with school children was very 

 much higher than either the values found in the 24-hour chamber 

 experiments included in table 38 or (more especially) the basal values 

 obtained by us. Of special significance are the two experiments of 

 Sonden and Tigerstedt with two sleeping boys, one 11 and the other 

 12 years of age. Their results, indicated by small crosses, lie very 

 near our basal values. 



As an approximate figure, one may state that the caloric output of 

 school children in the school-room would be, with boys, approximately 

 75 per cent above basal (see figure 33) ; with girls the increment would 

 be more nearly 50 per cent (see figure 34). Although not sufficiently 

 accurate for use in computing the entire 24-hour needs of growing 

 children, these figures are of distinct value in interpreting the food 

 needs of young children and the sum total of the day's activities of a 

 growing child. It is a tribute to the foresight and skill of the Scandi- 

 navian investigators to realize that now, after more than 25 years, 

 these experiments still remain of definite practical value. 



To sum up, we have in these two measurements, i. e., the basal 

 value and the value for school children, two steps in the important 

 computation of the 24-hour requirement. The basal requirement is 

 substantially the energy requirement during sojourn in bed, this 

 period with children varying from 8 to 10 or even 12 hours. The 

 school value will represent the requirement for 5 to 6 hours of the day. 

 It is thus possible to compute the total energy output for 16 to 18 



