A CRITIQUE OF THE BODY-SURFACE LAW. 



171 



live in sign they are also of a very material order of magnitude, ranging 

 from 24.9 to 113.8 calories or from 1.51 to 8.50 per cent of the average 

 heat-productions of the groups of individuals. In predictions involving 

 body-surface as estimated by the Meeh formula the use of equations 

 gives a smaller net deviation than computation of heat-production by 

 considering it proportional to body-surface. The differences are not 

 so large when measures of body-surface by the Du Bois height-weight 

 chart are used, but here 4 out of the 7 comparisons indicate by the 

 positive sign of the differences the superiority of the regression-line 

 method of prediction. 



TABLE 63. Differences in calories between the average deviations with regard to sign resulting 

 from the use of means and straight-line equations for prediction. 



If we consider together all of the tests of prediction by equations 

 as compared with prediction from the average values of metabolism 

 per unit of body-weight or body-surface area made in table 63, we note 

 that 17 out of the 21 differences are positive. In other words, predic- 

 tion from the mean heat-production per unit in the standard series 

 gives a larger average deviation with regard to sign than prediction 

 from equations. 



Turning now to comparison of the average deviations without 

 regard to sign, we have the results set forth in table 64. The first 

 column of constants shows the differences between the average devia- 

 tions (without regard to sign) of the predicted from the actually ob- 

 served heat-productions when the predictions are made by the use of 

 equations and when they are made from the average heat-productions 

 per unit of body-weight in the check series as a whole. The positive 

 signs (indicating a greater error of prediction when average heat- 

 production per kilogram of body-weight is used as a standard) show 

 that the equations give better results in every instance. 



