DURING POST-NATAL DEVELOPMENT. 



487 



soft tissues of the body, including the blood, have a specific gravity in the neighbor- 

 hood of 1.050. Fat is the least dense of these soft tissues. The human panniculus 

 adiposus has been estimated to have a specific gravity of 0.971 (Kapff). Fibrous 

 tissue is relatively heavy. The dermis of the human back has been estimated to 

 have a specific gravity of 1.394 (Kapff) and tendons that of 1.1165 (W. Krause and 

 G. Fischer). On the change in the specific gravity of the various tissues which may 

 take place between infancy and maturity we have no good data. 



The specific gravity of the human body as a whole has been investigated by a 

 number of authors with somewhat divergent results. The highest figures cited by 

 Vierordt are those of Krause, 1.0551 in quiet expiration, 1.1291 with air expelled 

 from lungs and gas from alimentary canal. At the other extreme, Hermann 

 gives a specific gravity of 0.9213 for normal cadavers, 0.9021 for individuals 11 to 

 20 years of age, and 0.9345 for individuals 21 to 40 years of age. The most 

 accurate work appears to be that of Meeh (1879) and that of Mies (1899), who 

 give somewhat similar figures. Meeh gives 1.01241 (extremes 0.978, 1.079) as the 

 specific gravity of four children 6. 70 to 13. 125 years of age, and 1.028 (extremes 1.013, 

 1.057) for seven males 16 to 45 years of age, in expiration. Mies gives an indi- 

 vidualized list of the boys and men whose specific gravity he determined. Appar- 

 ently the specific gravity was taken during shallow respiration with the chest 

 unexpanded. He summarizes the results as follows: 



TABI,E 1. 



The convicts in general he states were thinner than the other adults whom 

 he calls "ehrbaren" men. The specific gravity was determined, however, by 

 different methods in the two series. A few examples of his individual cases may 

 illustrate the relation of specific gravity to size of body. 



TABLE 2. 



