196 



SCIENCE 



[N. S. Vol. LIV. No. 1392 



which the author was to present it, experts and 

 those with varying degrees of knowledge could 

 master the main points of the thesis. They 

 would thus be prepared to join in, or to listen 

 to, a debate which would certainly be a real 

 contribution to the progress of knowledge. — 

 The London Times. 



SPECIAL ARTICLES 



ON THE LAW OF SURFACE AREA IN ENERGY 

 METABOLISM i 



The generalization that heat production in 

 animals is proportional to the surface of the 

 animal body rather than the weight of the body 

 was first hinted at by French writers before the 

 middle of the last century. It was formulated 

 rather definitely by Bergmann in 1848 and 

 was first placed on a definite footing of fact 

 almost simultaneously by Rubner in Ger- 

 many and by Eichet in France in 1885. This 

 so-called law of surface area has been quite 

 generally accepted and has contributed much 

 to the understanding of metabolism which we 

 now have. 



Eeeently this law has been submitted to 

 severe criticism by F. G. Benedict and his 

 colleagues- and the conclusion has been 

 reached that surface area is little or no better 

 as a measure of metabolism than is body 

 weight. The purpose of the present communi- 

 cation is to direct attention to some natural 

 limitations of the law of surface area which 

 seem to have been overlooked by these critics. 

 Harris and Benedict have rendered a service 

 to the science of metabolism and nutrition by 

 calling attention to the fact that since sur- 

 face is usually expressed as a quantity in 

 which two thirds power of the weight enters 

 as a factor it must of necessity be less variable 

 than the weight. As a matter of fact the 



1 Abridged from an address delivered before the 

 Torkville Medical Society, New York City, March 

 21, 1921. 



2 Harris, J. A., and Benedict, F. G., "A Bio- 

 metric Study of Basal Metabolism in Man," Car- 

 negie Inst, of Washington, Publ. No. 279, Wash- 

 ington, 1919; Benedict, F. G., and Talbot, F. B., 

 "Metabolism and Growth from Birth to Puberty," 

 Carnegie Inst, of Washington, Publ. No. 302, 

 Washington, 1921. 



mathematical relationship does not stop here; 

 for in many instances the constant employed 

 in the formula, for example, of Meeh or of 

 Lissauer, by which the two thirds power of the 

 weight is multiplied, equalizes the propor- 

 tions between surfaces and weights. A few 

 illustrations will make this clear. Suppose, 

 for example, we have two infants weighing 7 

 and 8 kilograms respectively. Expressing 

 their weights in grams and their surfaces in 

 sq. cm. by the Meeh and Lissauer formulae, 

 we have the proportions shown in the first 

 line of the following table. The ratio of 



Belation of Body Weights and Surfaces to Each 

 Other 



weights is .88 : 1 and of surfaces .91 : 1. 

 Now it is obvious that if the metabolism of 

 these two children is proportional to their 

 weights it must of necessity also be nearly pro- 

 portional to surface. With two youths weigh- 

 ing 40 and 41 kilos the surfaces bear to each 

 other exactly the same ratio as the weights, 

 whether the Meeh or Lissauer formula be em- 

 ployed. Both, therefore, will be equally good 

 measures of metabolism for the two individu- 

 als. The " discovery " that surface is no bet- 

 ter as a measure of metabolism, than weight 

 as between individuals of nearly the same 

 weight could, therefore, have been made with 

 paper and pencil. 



