NORMAL PEOCESSES OF ENERGY METABOLISM 597 



where A is the area in sq. cm., H the height in centimeters, W the weight 

 in kgm., and C a constant 71.84. A chart based upon this formula for 

 direct reading of the surface area when height and weight in metric units 

 are known is given in Fig. 33-a. 



b. Criticisms of the Law of Surface Area. Various criticisms have 

 been leveled at the law of surface area, some of them based upon fact and 

 some upon interpretation. Of the criticisms based upon fact that recently 

 published by Harris and Benedict is perhaps the most important. They 

 have subjected the body surface law to a critical biometric study and have 

 reached the conclusion that the correlations between body surface and basal 

 heat production in normal adults are of about the same magnitude as 

 those between body weight and heat production. "These results do not, 

 therefore, justify the conclusion that metabolism is proportional to body 

 surface and not proportional to body weight." In the opinion of these 

 authors the closer agreement between heat production of different indi- 



20 30 40 50 60 70 80 90 100 



WEIGHT-KILOGRAMS 



tlO 



Fig. 33-a. Chart for determining surface area of man in square meters from 

 weight in kilograms (Wt.) and height in centimeters (Ht.) according to the formula: 

 Area (Sq. M.) = Wt- - 428 X Ht- -' 25 X 71.84 (DuBois). 



viduals and their surfaces than between heat production and body weight 

 is not due to any causal relation between heat loss and heat production 

 as a mechanism for preservation of heat loss and body temperature, but 

 in part at least proceeds from the fact that body surface being proportional 

 to the % power of weight is less variable than the weight itself, and the 

 ratio of heat produced to body surface consequently is likewise less variable. 

 As a matter of fact the mathematical relationship does not stop here ; 

 for in many instances the constant employed in the formula, for example, 



