HEAT REGULATION. 



959 



surface area. As stated above, the average figure indicates a heat 

 production of 40 calories per hour per square meter of surface. 

 With advancing age there is a shght falling off in metabolism, 

 while in infancy and childhood there is a notable increase. The 

 relationship as pictured by these observers is illustrated in the 

 accompanying chart (Fig. 3016). In young children, therefore, 



Calories 



Allowances for activitij [or boys 

 according to different authors 



3-5 



10 I 15| |20; 25, 30< 35 ; 40 ; 45 *50 551^ 

 i 2 3450719 101112 13 14 15 16 1718 



Fig. 301c. — The heavily shaded area represents the allowance in calories per kilogram of 

 weight for basal metabolism; the lighter shaded area, the allowance for growth. The space 

 above the latter to the several lines gives the allowance for activity according to the estimates 

 of the different authors. Along the abcissa the lower line of figures gives the age: the upper 

 line, the approximate weight at each age. (From Holt and Fales, "Amer. Jour. Dis. of Chil- 

 dren," January, 1921.) 



the internal oxidations, as expressed by the basal metabolism, 

 proceed at a higher rate than in the adult, and this fact must 

 be borne in mind in arranging a dietary. In addition to the basal 

 metabolism the diet must also provide material for growth and 

 for muscular activity. The relative amounts of food necessary 

 to cover these three general requirements are expressed in the 

 curves given in Fig. 301c. The child must be fed more generously 

 than the adult when reckoned for a unit of surface or of weight, 

 although on account of his smaller total size and weight the 

 absolute number of calories is less. The estimated number of 

 calories per day at different ages is expressed in the curve given 

 in Fig. 301fZ. Under pathological conditions the basal metabohsm 



