442 C. R. BARDEEN 



The relatively smaller heart silhouettes of fat individuals appears 

 in groups of lighter weight for women than for men because heavy 

 women average less in height. See below for a discussion of the 

 effects of height. 



The figures in table 2 based on Dietlen's data show on the 

 average a close correspondence for the 187 men, a divergence of 

 only —0.01 per cent. We should, however, expect in this group 

 an average plus divergence of over 5 per cent since Dietlen's 

 observations were made on individuals- in the supine position 

 while the standard table is based on individuals in the sitting 

 position. The relatively small size of the silhouette area in 

 Dietlen's figures may be due in part to differences in method and 

 in part to racial differences. 



The relatively small size of the heart silhouette in Dietlen's 

 studies of women is more marked than in those studied by me. 

 Schieffer's studies of the hearts of individuals engaged in strenu- 

 ous muscular work show an average increase of 5.5 per cent of 

 the size of the heart shadow above the normal but since his 

 studies were made on individuals in the prone position, we should 

 expect about this difference from a standard based on the sitting 

 position. The lighter groups of individuals show relativelj^ 

 large heart shadows. 



Giegel ('14) suggested as a method of determining the heart 

 quotient, the division of the 3/2 power of the area of the heart 

 silhouette by the body weight in kilograms. He showed that the 

 heart quotient thus obtained varied in Dietlen's cases from fifteen 

 to twenty-three in 93 per cent of the cases. The extremes were 

 twenty-seven (two cases) and fourteen (three cases). Expressed 

 in terms of divergence from the normal standard this would mean 

 + 21 per cent to —9 per cent for the 93 per cent of cases, — 18 per 

 cent and +27 per cent for the extremes. The amount of diver- 

 gence from the standard fo\md in the normal individuals in the 

 groups studied by me will be discussed below in connection with 

 other factors which must be considered, age and height. 



The area of the cardiac silhouette estimated as 70 per cent of 

 the long diameter of the heart times the transverse diameter 

 gives for Claytor and Merrill an average divergence of —5.7 



