396 THE SCIENTIFIC MONTHLY 



This is not the place to trace the history of the so-called 

 body surface law, according to which heat production per 

 square meter of body surface is a constant. It has been widely 

 maintained since the days of the speculative writings of Berg- 

 mann, the comparative studies of Rameaux, and the experi 

 mental investigations of Miintz, Rubner and Richet. Of recent 

 years this so-called law has assumed practical importance in 

 that writers have maintained that the closest approximation 

 to the basal metabolism of a subject is given by 



where h is the required daily heat production, h s the average 

 heat production per square meter of body surface in a standard 

 series and s the body surface of the subject under consideration. 



The reader may be inclined to inquire why such a formula 

 is of practical significance. The answer should be evident on 

 a moment s reflection. Suppose the clinician wishes to investi 

 gate the influence of some disease, for example diabetes, on the 

 metabolism. A subject is selected from the hospital ward, 

 placed in the respiration chamber, and his daily heat produc 

 tion determined. This is merely a technical matter. The in 

 terpretation of the result presents a much more serious prob 

 lem. The caloric output of the subject in a pathological state 

 has no significance as indicating the influence of disease upon 

 metabolism until it can be compared with a normal value. With 

 what normal constant shall it be compared? Naturally, with 

 that which would be expected for the same individual in good 

 health. Thus the theoretical metabolism of the subject in health 

 must be taken as a basis of comparison for his actually meas 

 ured metabolism in disease before one can draw any conclu 

 sions whatever concerning the influence of the disease. 



Again, suppose that stringent rationing is under considera 

 tion. What ration shall be allotted to individuals of various 

 sizes? Clearly, both the most just and the most advantageous 

 procedure would be to allow them food proportional to their 

 physical needs. 



Now one of the crucial tests of the validity of a law is its 

 capacity for predicting the unknown. If the &quot;body surface 

 law,&quot; expressed by the above formula, serves to predict the 

 heat production of a subject more precisely than any other for 

 mula, it must certainly take its place as one of the most impor 

 tant empirical laws in nutritional physiology. 



This problem has been investigated in great detail in the 

 extensive data collected at the Nutrition Laboratory during the 



