122 A BIOMETRIC STUDY OF BASAL METABOLISM IN MAN. 



consistent than those for age and gross heat-production. The differ- 

 ence between the two sexes is only 0.1 122 0.0703, and is therefore 

 insignificant in comparison with its probable error. The difference 

 between the two correlation ratios is 0.1281 =*= 0.0647, or approximately 

 twice its probable error and of questionable biological significance. 

 Applying Blakeman's criterion we find : 



For men ................... 



For women ................ 



On the basis of the usual criterion, regression can not be asserted 

 to be non-linear in either sex. 



Turning now to the measures of heat-production corrected for 

 body-size by reduction to calories per square meter of body-surface 

 by the Du Bois height-weight chart, we have for r ah and r iajl : 



Correlation Correlation 



coefficient, r. ratio, >). 



For men ................ -0.4584 0.0457 0.5008 0.0433 



For women. . . -0.5149 0.0489 0.5824 0.0439 



Difference ........... 0.05650.0669 0.08160.0617 



Again the differences between the constants for men and women 

 can not be considered to differ significantly. Blakeman's criterion gives 



For men ................ /E = l.SQ For women 



The results can not be considered to show that regression is non- 

 linear. The calculation of the correlation ratios and the interpretation 

 of the results of Blakeman's test on a series of only 136 and 103 indi- 

 viduals presents some difficulties. We have not applied the corrections 

 to the correlation ratio suggested by Pearson and " Student," never- 

 theless we feel justified in concluding from the results of Blakeman's 

 test and from the graphical test of the linearity of regression that 

 throughout the age range involved the change in metabolism with age 

 can be satisfactorily represented by a straight line. When larger series 

 of data are available the use of regression coefficients of a higher order 

 may be justified. 



A discussion of the practical application of correction for age is 

 reserved for Chapters VII and VIII. Before leaving the subject of 

 the change of metabolism with age, it seems desirable to compare the 

 heat-production per square meter of body surface by the Du Bois 

 height-weight chart given by our equations for total men (N = 136) 

 and for total women (N = 103) with the "normal standards" for various 

 ages calculated by Aub and Du Bois n from their age curve and that 

 given by Lusk. 12 



11 Aub and Du Bois, Arch Intern. Med., 1917, 19, p. 831. Also Cornell, Univ. Med. Bull., 



1918, 7, No. 3, 19th paper, p. 9. 



12 Lusk, Science of Nutrition, Philadelphia, 3 ed., 1917, p. 129. 



