460 C. R. BARDEEN 



the bod}^ weight been normal for height and age we get the re- 

 sults shown in the column at the right in tables 10 and 11. The 

 weighted average for males is 0.469 per cent, for males above one 

 year of age 0.459 per cent. The weighted average for females is 

 0.455 per cent, for females above one year of age 0.434 per cent. 

 In six of the weight groups of the males the per cent of mean 

 body weight is less than 0.46 per cent, in five greater than 0.46 

 per cent. The highest percentage 0.554 per cent is found in the 

 80-90 K. group. The lowest 0.436 per cent in the 20-30 K. 

 group. In eight of the weight groups of the females the per- 

 centage is below 0.46 per cent, in three 0.46 per cent .or higher. 

 The highest percentage, 0.514 per cent is in the 1-10 K. group, 

 the lowest, 0.341 per cent, in the 80-90 K. group. 



Thoma from a mathematical study of a less extensive material 

 than that of MiiUer but carefully selected, found an average 

 heart-muscle body- weight ratio of 0.463 per cent. This figure 

 lies midway between the averages given above for the mean 

 body weight in men and that in women. In round numbers we 

 may take the heart muscle weight to be approximately 0.46 per 

 cent of the body weight in individuals of normal build, slightly 

 higher in men, slightly lower in women, higher in thin individuals, 

 lower in fat individuals. 



The Miiller data arranged according to height (table 12) 

 show the relative heart muscle weight ranging from 0.501 per cent 

 to 0.532 per cent, in men, but this relatively high figure is due as 

 pointed out above to the inclusion of a large proportion of 

 relatively thin individuals. 



According to Miiller there is an increase in the relative 

 weight of the heart with age irrespective of size of body as illus- 

 trated in table 13. However, it must be remembered that there 

 is normally an increase in weight during adult life until old age 

 comes on. The heart enlarges to meet this increase in weight. 

 Sickness reduces the weight of the body usually more than the 

 weight of the heart musculature so that after death the heart 

 may appear relatively large in proportion to body weight. 



The relative distribution of the musculature within the heart 

 has been studied by several investigators among whom the work 



