462 C. R. BARDEEN 



Taking the relative weight of the heart musculature to be 

 0.46 per cent of the body weight we may next consider the weight 

 of the non-muscular structures. Of the non-muscular structures 

 fat constitutes the chief mass after jearly infancy. The most 

 careful study of the amount of fat in the heart is that of W. 

 Miiller. He has shown that amount of fat in the heart increases 

 with age. In the new born there is relatively little but later 

 in life it constitutes no inconsiderable part of the weight of the 

 heart. Part of the fat is as a rule easily removed with the peri- 

 cardium but about 8 per cent can be removed only when special 

 methods are used. The average amount of fat may be illustrated 

 by the following table based on data from Miiller (table 14) . 



The body weight is estimated from data given in table 8. 



The relative amount of fat may be judged by comparing the 

 weight of the heart as a whole at various ages with the weight 

 of the heart muscle as shown in the following table (table 15). 



The data concerning the weight of cardiac fat relative to body 

 weight given in table 14 do not quite correspond with the data 

 of table 15, owing probably to some variation in the individuals 

 composing the various age groups but the differences in the two 

 tables are not serious. To some extent, at least, the greater 

 amount of fat found b}^ Mueller in the older age groups is due 

 to the greater emaciation of the younger as compared with the 

 older individuals studied by him. A rough estimate of the de- 

 gree of emaciation may be made by comparing the average 

 body weight for each of the ^Miiller age groups with the body- 

 weight estimated as normal for a given age and height in tables 

 A and B. This comparison shows that while the new born in 

 Miiller table are of about normal weight male infants during 

 the first year of hfe are nearly 50 per cent underweight and 

 during the second and third years about 33 per cent underweight. 

 After this period the average body weight for each age group 

 appears to be only from 25 to 30 per cent under the weight of 

 healthy living individuals during youth, 20 to 25 per cent during 

 adult life until the oldest age period when the average body 

 weight seems to be 40 per cent underweight. The female in- 

 fants appear to be 4 to 50 per cent underweight, girls up to ten 



