METABOM ">ll 



terns being then cul out, and weighed. Prom I ults it wa to 



calculate the acl ual surface area. 



Where the heighl and weighl are known, a fairlj accurate computation 

 of tlif surface can be secured by using the following formulas: A W 



II 71.84 j .1 being the surface area in Bquare centimel H 



heighl in centimeters; and W } the \\ • • i lt 1 1 1 in kilograms. Based on this 

 formula, a charl has been plotted from which the surfi de- 



termined ;ii a glance Fig. 175 . Another method recently emplo; 

 Benedicl Is based on measurements made from photographs of the subj 

 in various post s. 



By the use of these more accurate measurements of body surface, it - 

 now known that, although the surface-area law gives us eonstanl results 

 for the energy outpul of differenl individuals of similar build, and off< 

 us a much more accurate basis for comparing th differenl laboratory 



animals than body weight, yel it breaks down when applied to men in widely 

 differing states of body nutrition. Thus, in the case of a man wl ved 



for a month, the calorie output per square meter of surface decreased I 



wards tl nd of the fast by 28 per cent. Obviously, therefore, it would be 



incorreel to draw conclusions regarding possible ili.i mr< ^ in energy output 

 of a series <>t' emaciated or corpulenl individuals by <->>ni pai-ist >n of their 

 calorie output per square meter of surfj with that of normal individuals. 



Tlic determining factor of energy output is undoubtedly the ral 



condition of bodily nutrition — the active mass of protoplasm of the body 



Benedict). Thai there is a relationship between the body Burface and 



metabolism is undoubted, bu1 the relationship is not a causal one. Al 



aent, therefore, the onlj - ■ method to employ in comparing 

 metabolism of normal and diseased individuals is that called by Benedict 

 "the group method," in which the metabolism of groups of : 

 like height and weighl is compared, ii being assumed that such individuals 

 have the Bame general growth relations. For the application of this group 

 method, however, more extensive data will be required than exist at p 

 rut. and although some of the conclusions drawn from results comput 

 the Burface-area 1»a^is may have to he revised, ii is probable thai 

 are in general correct. 



Influence of Age and Sex 



The energy output is low in the newly born; it inc 

 the first year, reaching a maximum at about thr< 

 then rapidl} declining to aboul twenty, after which i* declines much n 

 slowly. The decline in the earlier years do lily. 1 

 ever, tor at the period jusl preceding the oi puberl i in- 

 crease In mes evident, indicating that at this 



