556 VI. OCCURRENCE OF LIPIDS IN THE ANIMAL 



these values are not the highest predicted levels of total fat, they do cor- 

 relate well with specific gravity, and the locations are readily accessible for 

 measurement in both sexes. The best indicator of total fat can be obtained 

 in men by measurement of the chest skinfold above the nipple. 



Ordinarily, the actual values of the skinfolds can be used as a criterion of 

 fatness. One may employ the thickness of one skinfold (one-half the 

 mean skinfold minus the average skin thickness) or a mean of several skin- 

 folds, treated in the same way, or a combination of several skinfold meas- 

 urements in the form of a multiple regression equation, body fat being con- 

 sidered the "dependent" variable. 



Keys and Brozek 166 postulated that a relative value for the skinfolds in 

 which the body size was included might be a better index of the degree of 

 fatness than the absolute measurement. This value could be calculated 

 from the following equation : 



_ ,. , , , , . S (skinfold measurement) X A (surface area) 



/ (index of fatness) = — J „, ,, , . ,, . 



v M (body weight) 



If the true average value of the thickness of subcutaneous fat is available, 

 SA would represent the volume of subcutaneous adipose tissue ; by multi- 

 plying this by the density value one could obtain the total weight of the 

 subcutaneous fat. 



b'. Fat-Skeleton-Muscle Analyses: Matiegka 174 based his calculations of 

 skeleton, skin plus subcutaneous fat, and muscles upon stature and upon 

 the anthropometric characteristics of the extremities. The skinfold meas- 

 urements were employed in these calculations, which, however, were not 

 validated by determinations of these values on corpses. Edwards 175 pre- 

 sented mean "fatfold" thicknesses (skinfolds less the average values for 

 double skin thickness) at each of fifty-three sites in female subjects with an 

 average weight of 148 lb. Neither height nor average age was specified. 



c\ Roentgenograms: Apparently Stuart et al. m were among the first to 

 measure the thickness of the subcutaneous fat layer by the application of 

 roentgenography. The technic was developed further by Stuart and 

 Sobel, 177 and by Reynolds, 178 who used children as subjects. This technic 

 was also employed in the tissue analysis of children in Madrid, 179 as well as 



176 H. C. Stuart, P. Hill, and C. Shaw, The Growth of Bone, Muscle, and Overlying Tis- 

 sues as Revealed by Studies of Roentgenograms. Monogr. Soc. Research Child Develop., 5, 

 Ser. 26, No. 8, Child Develop. Publ., Evanston, 111., 1940, pp. 1-189. 



177 H. C. Stuart and E. H. Sobel, J. Pediat., 28, 637-647 (1946). 



178 E. Reynolds., Child Develop., 15, 181-205 (1944). 



179 W. D. Robinson, J. H. Janney, and F. (Covian) Grande, J. Pediat., 20, 723-739 

 (1942). 



