Chart B Curve of increase of femoral density with increased resistance 

 due to hind-limb weight. The resistances to femoral growth are as follows: 1) 

 Weight of the hind limb; 2) reactive force of elasticity of traction of the forming 

 muscles; 3) active muscular pull; 4) opposition to interstitial femoral growth at 

 the ends by the acetabulum proximally and the tibia distally. 



The specific gravity of these femora was determined by immersion in various 

 concentrations of benzene (sp. gr. 0.879) and chloroform (sp. gr. 1.499). The 

 specific gravity of that solution in which a certain femur would neither rise nor 

 sink was determined by means of the pyknometer; this method gave the specific 

 gravity of the femur. The details of this method will soon be published, with 

 my colleague in biochemistry, Dr. Joseph C. Bock. 



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