397 



past decade. These are now so numerous that it is possible to 

 use one fraction of the records as a basis of prediction equa 

 tions, and to test the validity of these equations by considering 

 the metabolism of other actually measured individuals as un 

 known, calculating their caloric output by the various methods, 

 and determining which formula gives the closest prediction. 

 That formula which estimates the metabolism most exactly 

 from measurable physical characters must be looked upon as 

 the most valuable empirical law. 



It must be admitted that the &quot; body surface law &quot; has given 

 excellent results. If, however, there be no purely physiological 

 basis for assuming a causal relation between body surface and 

 heat production it would seem desirable, if possible, to replace 

 &amp;gt;this formula by a more rational one. 



The foregoing analysis has shown that weight, stature and 

 age all have independent significance for predicting the metab 

 olism of the individual. Availing ourselves of the constants 

 showing the independent relationship between these easily 

 ascertainable characters and metabolism, we deduce the follow 

 ing multiple prediction equations : 



For men h = 66.473 + 13.752 w + 5.003 s 6.755 a. 



For women h = 6^5.096 + 9.563 w + 1.850 s 4.676 a. 



6&quot; 



where w=body weight in kilograms, s = stature in centi 

 meters, and a = age in years. 



These equations make possible the closest prediction of the 

 daily caloric output of an unknown subject. They are particu 

 larly well adapted to practical work. To calculate the most 

 probable metabolism of any subject it is only necessary to sub 

 stitute the actual values of weight, stature and age in the equa 

 tion ; for example, A. S. F. is a man 21 years old, weighing 69.3 

 kilograms, and 169 centimeters in height. His most probable 

 daily heat production will therefore be given by 



h= 66.9173 + (13.752X69.3) + (5.003X169) (6.755 X 21) = 1723 calories. 



f 

 His actually measured heat production was 1,733 calories, 



or there was an error of only 10 calories per twenty-four hours 

 or of 0.6 per cent, in predicting his metabolism from two physi 

 cal characters and age. 



The result is unusually good. K. G. M. is 32 years old, 

 weighs 68.8 kilograms and is 171 centimeters tall. His daily 

 heat production should, therefore, be given by 



h = 66.473 + (13.752 X 68.8) + (5.003 X 171) (6.755 X 32). 



The equation gives 1,652 calories as compared with 1,889 



