144 A BIOMETRIC STUDY OF BASAL METABOLISM IN MAN. 



the variability about (that is above and below) the mean value is 

 10.6 and 7.5 per cent of this mean value in adults and infants 

 respectively. 



What is the real significance of this result? It shows that physiolo- 

 gists have been regarding as a constant a figure which when actually 

 determined shows a variability about two or three times that of stature 

 in man ! Surely no careful observer would consider the statures of the 

 men he passed on the street identical. Yet physiologists have been 

 using a selected value from series two or three times as variable and 

 dignifying it as a "constant." 



While the present discussion is limited to the problem of the validity 

 of the surface law in man, it is not without interest to note that Moul- 

 ton, in his investigation of the surface area of cattle, 62 has found a 

 wide variation in the value of k. The formulas which he proposes 

 to use differ according to the fatness of the animals. 



Determining the statistical constants of the values of k entered 

 in table 5 of Trowbridge, Moulton and Haigh, we have : 



A; =9.097 o* =0.8915 F fc =9.80 



Again we find a variation in the values of the "constant" which is 

 relatively large, that is about 10 per cent of the average value. The 

 futility of using a "constant" which is so little constant as this k is 

 fully admitted by Trowbridge, Moulton and Haigh when they use 

 different values for animals in different conditions. 



Thus the Meeh method is no more satisfactory in its application 

 to animal than to human calorimetry. 



Fortunately conditions in work on human metabolism have been 

 much improved by the studies of Du Bois and Du Bois, resulting in 

 the development of the linear formula and of the height-weight chart 

 which has been used throughout this chapter and which is destined to 

 replace entirely the Meeh formula. Computations based upon the 

 latter have, however, been given along with those based on the height- 

 weight chart in many of the tables of the following discussion, since 

 historically the theories considered date from the time when the Meeh 

 formula was the only one available. 



4. INADEQUACY OF CRITERIA OF VALIDITY OF BODY-SURFACE 



LAW HITHERTO EMPLOYED. 



There has been in the past and prevails at present great diversity 

 of opinion concerning the validity and range of applicability of the 

 surface law. These differences of opinion are founded in part on tradi- 

 tion. In so far as they rest upon study of the available facts concerning 



6 - Trowbridge, Moulton, and Hai>;h, Univ. Mo. ARHC. Expt. Sta., Research Bull. No. 18, 1915, 

 p. 14. Moulton, Journ. Biol. Chem., 1916, 24, pp. 303-307. 



