DETERMINATION OF SIZE OF HEART BY X-RAYS 445 



instances estimated from the displacement of water or oil by the 

 empty heart. While data of this kind are necessarily crude, 

 especially since the bodies utilized were the regular material used 

 in teaching medical students, it is believed the data obtained 

 have some value, especially in connection with x-ray studies on 

 the living. 



Twenty-four adult male bodies show an average divergence 

 from the normal standard of +3.9 per cent, nine females an 

 average divergence of +7.2 per cent. The individual variations 

 are to be attributed in part to variations in the extent of dis- 

 tention of the heart after embalming. The relatively few female 

 bodies studied do not lend support to what seems to be on other 

 evidence fairly well established that the female heart relative to 

 body size is slightly smaller than the male. 



The foetus and one of the new born infants studied show small 

 hearts, the other new born, a large heart. One of the young 

 children shows a small heart, the other two large hearts. The 

 nine year old child shows a heart small from the standpoint of 

 area and from the standpoint of weight. While the data here 

 given for children are scanty they tend on the whole to lend 

 support to the belief that the standards of tables A and B are 

 approximately correct for young children. 



b. Silhouette area and transverse diameter 



The transverse diameter varies in size in relation to the area 

 of the heart silhouette and the volume of the heart according to 

 the position of the heart. If the long axis of the heart is trans- 

 versely placed, as during childhood and in fat adult individuals, 

 the transverse diameter of the silhouette is relatively large. 

 If the long axis is more nearly vertical as is usual during youth 

 and in thin adult individuals, the transverse diameter of the 

 silhouette is relatively small. I have found far wider variations 

 in the transverse diameter than in the area of the heart silhouette 

 in relation to the size of the body. To compare the extent of 

 variations of transverse diameter with those of area the former 

 should be squared. If this be done the variations in transverse 



THE AMERICAN .lOURNAL OF ANATOIJV, VOL. 23. NO. 2 



