118 



METABOLISM AND NUTRITION 



a large and a small, warm-blooded animal with fur of the same thickness are to 

 have the same bodily temperature in the same atmospheric temperature, the 

 small animal must produce more heat in proportion to its weight than the large 

 one i. e., the metabolism per kilogram of weight must be greater in the former 

 than in the latter (C. Bergmann). 



In the experimental proof of this relationship which Rubner furnished later 

 (above table numbers 2-8), he measured the superficial area of the body and 

 calculated the metabolism per square meter of the surface. It proved to be 

 the same for all the dogs regardless of size (last column of the table). The same 

 relationship is demonstrable also for animals on food. 



That the growing organism has a greater metabolism per kilogram of 

 weight than has the adult, is evident from the mere difference in size. But 

 experiment shows further that when calculated per square meter of surface, 1 

 the metabolism in younger individuals is higher than in older ones; in other 

 words, the metabolism is influenced by something peculiar to the young body, 

 which serves to keep it at a higher pitch. 



The following table contains a number of observations by Magnus-Levy 

 and Talk in support of this statement. They were made on individuals who 

 had not eaten for some time and who were resting quietly, lying down. 



The few direct observations which we have on the total metabolism of 

 growing children give the same result, as will be seen from the following 

 summary : 



1 The following formula devised by Meeh is used in calculating the superficial area of 

 the body from its weight: A = c%/W 2 , where W is the weight in grams and c is a constant 

 empirically determined for each animal speries. This constant varies somewhat with age, 

 and for man it has a mean value of 12.3, for the dog, 11.2, for the rabbit, 12.9, for the rat, 

 9.1, and for the guinea pig, 8.9. 



