A CRITIQUE OF THE BODY-SURFACE LAW. 



147 



For calories per kilogram per hour : a = 0.0908 V = 8.67 



For calories per square meter per hour : a = 1.962 V = 5.74 



The results confirm those obtained by the average deviation in 

 indicating greater variability in measures of heat-production per unit 

 of weight. 



The same point may be brought out in a somewhat different and 

 not altogether satisfactory manner by comparing the coefficients of 

 variation for number of calories per kilogram of body-weight with the 

 coefficients of variation for calories per square meter of body-surface 

 in our various adult series. This is done in table 49. 65 



TABLE 49. Comparison of coefficients of variation of heat-production expressed 



in various units. 



On first consideration these results would seem to fully justify the 

 assertion that among groups of men of varying weight metabolism is 

 proportional to surface-area according to Rubner's law and is not 

 proportional to body-weight. Extreme caution must, however, be 

 exercised in the physiological interpretation of such a relationship. 

 The fact that the measures in terms of calories per square meter of 

 surface show a smaller percentage of variation from their average 

 value than do measures in terms of calories per kilogram of body-weight 

 does not necessarily have any relationship whatsoever to physiological 

 constants or to causal physiological relationships. 



Consider this question somewhat more minutely. A series of meas- 

 urements of total heat-production, h, in n individuals are made. These 



are hi, h?, h-< 



h n . The body-surfaces Si, s 2 , s 3 , 



s n and the 



65 This method of analysis has the disadvantage that coefficients of variation are calculated 

 from ratios of heat-production to body-weight and to body-surface. Thus an index of an index 

 is used. 



