A BIOMEmiC STOBY OF BASAL, METEABOIJ&lt KM MAW. 



the average basal metaboliiffim off normal men fe measured by a 

 daily heat-production off about 1600 to 1650 calories. AM the series, 

 even those in which the number off individraals is very sanmgainL are reason- 



Women show am average dafllyheatr-piroduetion, wfeeim in 

 complete muscular repose and in the post-absorptive state, of about 300 

 calories per day less than men. The average daily basal heat-production 

 of new-born infants is> as shown in table 5, about 140 to 145 calories. 

 This is about 10 per cent of that of adult women. In 



these values one must, however, remember that they are uncorrected 

 for the influence of stature, body-weight, or age* all of which have 

 important roles as proximate factors in the determination of the basal 

 dauy heat-production of the individual. 



The second column shows the great variability in basal heat- 

 production from individual to individual- The variabilities range 

 from 142 to 215 calories for men and from 150 to 165 calories for women. 

 For the larger series 140 to 230 calories for men and 150 to 160 calories 

 for women maybe taken as the variabilities expressed in round numbers. 

 It is evident that with such large variations in the daily basal metabol- 

 ism of the normal individual the prediction of the heat-production of 

 an individual subject will always have a high probable error that is, 

 a limited tnist worthiness. In infants the standard deviations are 

 about 21 to 23 calories per day (table 5). 



In speaking of standard deviations of 140 to 230 calories for adults 

 and of 21 to 23 calories for infants as large, one must not forget that 

 these are for organisms giving daily average heat-productions of 1300 

 to 1650 calories for the adult and of 140 to 145 calories per day for the 

 infantile state. If the standard deviations be expressed as percentages 

 of the average daily hea i -product ion we have the constants in the 

 third column of table 5 for the infants and table 16 for the adults. 

 To gain a definite idea of the relative variability of basal metabolism 

 as compared with other more familiar physical magnitudes and physio- 

 logical activities, it seems worth while to examine these constants in 

 some detail. 



First of all we note that the values range from 8.85 to 14.08 per cent 

 for men and from 11.05 to 12.31 for the women, with constants for 

 the whole series of data for the two sexes of 12.54 =*=0.52 for the men 

 and 11.50 =*=0.55 for women. These values can not, with due regard to 

 their probable errors, be asserted to differ significantly. 



In the infants the coefficients of variation are somewhat higher, 

 being 14.46 for the boy babies, 16.54 for the girl babies, and 15.49 for 

 infants irrespective of sex. The difference between the two sexes is 

 2.08=*= 1.59, which is statistically insignificant and hence can not be 

 regarded as indicative of a real physiological difference in variability 

 of heat production between the sexes. 



