DISCUSSION OF RESULTS. 157 



nourished, so that although the use of the base-line of per kilogram of 

 body-weight may be justified when comparing individuals of average 

 weight and approximately constant body composition, i. e., with no great 

 differences in the proportion of body-fat and muscular tissue, yet when 

 comparing bodies of widely varying body-weight and body-composition, 

 this basis of comparison can not be considered reliable. 



RELATIONSHIP BETWEEN BODY-SURFACE AND METABOLISM. 



For many years writers in metabolism have been wont to emphasize 

 the significance of the relationship supposed to exist between the metab- 

 olism and the body-surface rather than that between the metabolism 

 and the body-weight. The idea that there is an intimate relationship 

 between body-surface and heat-production was first brought out by 

 Bergmann 1 in 1847. The theory lay dormant for many years, but 

 was finally resuscitated and put forth in a brilliant and highly stimu- 

 lating manner by Rubner 2 in 1883, together with experimental evidence. 

 Based fundamentally upon Newton's law of cooling, it received great 

 attention from practically all workers in physiology. Startling evidence 

 was brought forward to demonstrate that the heat-production per 

 square meter of body-surface was about 1,000 calories for practically 

 all species of animals, and this lent further support to the hypothesis. 

 In connection with our own researches we naturally expected to find 

 a close relationship between body-surface and total metabolism, par- 

 ticularly in view of the fact that recent observations from foreign 

 laboratories appeared to confirm the validity of Rubner's law. We 

 were therefore greatly surprised on preparing our final figures to find 

 this intimate relationship entirely disturbed. 



METHODS USED FOR MEASUREMENT OF BODY-SURFACE. 



In order to discuss intelligently the relationship between the metab- 

 olism and body-surface, a critical examination of the various methods 

 for determining the body-surface is essential. Using as a basis the 

 relationship between the surface of similar solids which is expressed 

 by the cube-root of the square of the weight, efforts have been made 

 by a number of investigators to compute the body-surface of various 

 animals and individuals from the body-weight. 



Meeh 3 found that he could measure the body-surface of men by 

 using the constant 12.312, which, when multiplied by the cube-root 

 of the square of the body-weight in grams, gave the body-surface in 

 square centimeters. Rubner and Heubner, 4 who first applied this 

 formula to the study of the total metabolism of infants, rightly sub- 



^ergmann and Leuckart, Anatomisch-physiol. Uebersicht des Thierreichs. Stuttgart, 1852. 

 p. 272. See also, Bergmann, Wanneokonomie der Thiere. Gottingen, 1848, p. 9. 

 2 Rubner, Zeitschr. f. Biol., 1883, 19, p. 545. 

 3 Meeh. Zeitschr. f. Biol. 1879, 15, p. 425. 

 'Rubner and Heubner, Zeitschr. f. exp. Pathol, u. Therapie, 1904-1905, 1, p. 1. 



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