ANTHROPOMETRIC DATA. 243 



would therefore be: f:l'^::a:x, I representing the length of the 

 metric scale as photographed (0.0875 meter), a the area of the photo- 

 graph expressed in square meters (0.00264 square meter), and x the 

 actual surface area of the section of the body shown in the photograph. 



The general equation would be : x=p' The actual surface area of the 



section of Gar's body shown in the photograph would thus be 0.00264 

 sq. meter divided by 0.0076o or 0.345 sq. meter. Using the factor 

 5.02, which represents the relationship found to exist between the 

 surface of the body shown in pose C and the surface of the whole 

 body, we find that the body-surface of this subject as computed from 

 the silhouette photograph is 1.73 sq. meters.^ 



With Squad A in September, when the first measurement was ob- 

 tained, the surface areas as computed by the Du Bois formula are 

 almost invariably higher than those found by the height-weight chart, 

 while in November, at the time of the minimum weight, these dif- 

 ferences practically disappear. We are somewhat at a loss to under- 

 stand why there should be this variation, for the measurements were 

 made with great care, although admittedly under considerable ten- 

 sion. The discrepancies are, however, not very great, but singularly 

 enough lie almost invariably in one direction. When the values 

 computed from the Du Bois formula from the set of measurements 

 made on February 2 are compared with those calculated from the 

 height-weight chart, we find a very close agreement for practically 

 all of the subjects. The widest discrepancy is that with Mon, the 

 values being 1.78 sq. meters for the Du Bois formula as compared 

 with 1.72 sq. meters found with the height-weight chart. It is further 

 noticeable that the differences are plus or minus, that is, the averages 

 of the two areas for the squad as a whole would be nearly the same, 

 irrespective of whether it was determined by the Du Bois linear 

 formula or by the height-weight chart. 



With Squad B a comparison between the results obtained with 

 the Du Bois linear formula and the height-weight chart shows, for the 

 most part, excellent agreement. For the measurements taken January 

 5, i. e., before weight-reduction, the widest difference is found with 

 Sch, the values being 1.84 sq. meters for the Du Bois formula as 

 against 1 .77 sq. meters for the height-weight chart. With the measure- 

 ments taken after the reduction in weight (January 27), there is like- 

 wise fairly uniform agreement between the results obtained on the 

 two bases of measurement. Sch again shows the greatest discrepancy, 

 with 1.78 sq. meters for the Du Bois formula, as opposed to 1.71 sq. 

 meters for the height-weight chart. In these later comparisons, how- 



* Reference to the original description of the photographic method (Benedict, Am. Joum. 

 Physiol., 1916, 41, p. 275) should be made for the technique of taking these photographs and 

 other details of this method of calculating the surface area. 



