4 A BIOMETRIC STUDY OF BASAL METABOLISM IN MAN. 



constants of a series of individuals is made by reducing them to units 

 of body-weight or body-surface indicates that the total metabolism of 

 the individual is correlated with his physical characteristics. Thus 

 the desirability of a detailed investigation of the correlation of the 

 various physical and physiological measurements which have been 

 made suggests itself. 



Such investigations of variation and correlation can be carried out 

 only by means of the biometric formulas. A full justification for the 

 application of the higher statistical methods to the data of basal 

 metabolism is to be found in the fact that these methods have been 

 successfully applied in other fields in which the observational data 

 exhibit comparable irregularity. During the past two decades instances 

 of the demonstration of law and order in processes hitherto apparently 

 chaotic have been rapidly multiplying, while on the other hand, long- 

 maintained biological theories have been shown to be groundless by 

 the mathematical description and analysis of series of measurements. 

 This fact establishes a strong presumption that the same condition will 

 be found to apply in the field of human metabolism. The presumption 

 has seemed to justify at least a preliminary test of the methods. 



It seems desirable to outline at the start the possibilities of the 

 statistical formulas in their application to the problems of basal 

 metabolism. 



First of all, these formulas permit a more concise and adequate 

 descriptive statement of the results of experimentation. The statistical 

 method furnishes not merely an average measure of metabolism, but 

 also a measure in a single constant of the deviation of the individual 

 determinations of metabolism from their average value. The average 

 value of the metabolism constant serves many useful purposes, but it 

 is no more truly a characteristic of the series of measurements which 

 have been made than their differences among themselves. Measures 

 of variability in metabolism are, therefore, quite as necessary for a 

 full understanding of the physiological problem as are measures of the 

 average values. Such constants have been determined during the 

 course of this work, and expressed in both absolute and relative terms. 

 The measures in absolute terms are particularly useful for some pur- 

 poses, while those in relative terms permit direct comparison of the 

 variability of metabolism constants with those of other physical and 

 physiological measurements in man. 



Again, one of the greatest possibilities of the statistical method lies 

 in the determination of the degree of association or correlation of differ- 

 ent physical and physiological or of different physiological characters. 

 For example, we know that in general the total heat-production of a 

 tall individual is greater than that of a short individual, that the heat- 

 production of a heavy individual is greater than that of a light individ- 

 ual, and so on. But what is needed for a full and scientific analysis of 



