200 SECTIONAL ADDRESSES 



carbohydrate is taking place or vice versa. Since these conversions are 

 ephemeral and will cancel each other over a long period, they can hardly 

 be regarded as part of a ' standard ' metabolism, and so it is much better 

 to neglect them, and this is done by taking the carbon dioxide alone into 

 consideration. In these circumstances the basal or standard metabolism 

 must be defined afresh as the heat of combustion at rest in the post- 

 absorptive state and not as the total heat measured in a calorimeter, the 

 value of which may be a little different, depending on the respiratory 

 quotient. If this definition be accepted it follows that the carbon dioxide 

 alone must be measured and no account must be taken of the intake of 

 oxygen. 



Standards of Metabolism, Growth, and General Nutrition 



IN Children. 



In working out a new standard of basal metabolism from the COg it was 

 decided, as Benedict has done, to determine t^ie mathematical correlation 

 between the four quantities, carbon dioxide excretion, body weight, height, 

 and age, irrespective of any preconceived theory that might possibly relate 

 them together ; but, as in Meeh's and Dreyer's formulae and in the 

 height-weight formula of Du Bois, the Calories were related to a power 

 of the body weight, it seemed advisable as a first step to plot the logarithms 

 of the body weight and carbon dioxide output with a view to determining 

 graphically what the power was. This was a fortunate step as, in the 

 case of the children, it at once indicated that between 1-2 and 4-5 years 

 of age there was a break in the continuity of the curve relating these 

 quantities ; further work showed a closer correlation between CO 2 and 

 height up to 5-6 years of age than between CO 2 and weight, since some 

 children were unusually heavy, possibly from retention of fluid associated 

 with hypothyroidism. At these ages height is the best measure of 

 metabolism. As the baby grows from birth to a height of 29 in., i.e. 

 up to I year, the regression equation is as follows : 



Early infancy : 



Log. CO2 = 3-15 log. height -4-04 . . (14) 



Between 29 in. (i year) and 41J in. (5-6 years) it is 



Log. CO2 = 046 log. height + I . . . (15) 



In other words, there is but little increase in COj with growth between 

 heights of 29 and 41 J in. ; subsequently up to about puberty there is 

 again a larger increase in the CO 2 output, and it is now higher for boys 

 than for girls. These CO 2 values of Benedict and Talbot are probably 

 on the low side, though they are consistent in themselves ; but the recent 

 results of R. C. Lewis * and others will have to be investigated in order to 

 obtain a more correct prediction of the COg from the height or weight of 

 children above 5 to 6 years. 



* Amer. Jour. Dis. Child. 1937, 53, 348. 



