BONE. 553 



Some of the C02 is always lost on calcining, so that the bone-ash 

 does not contain the entire C02 of the bony substance. 



GAUTIER and CLAUSMANN 1 have determined the fluorine in various 

 organs and tissues. In man the diaphysis end of the femur had 0.495 

 p. m. fluorine, and the epiphysis end 0.119 p. m. fluorine. In children 

 the diaphysis end of the long bones contained 0.156 p. m. fluorine 

 and the epiphysis end 0.037 p. m. A similar difference also occurs in 

 animals. Cartilage of man with 0.014 p. m. fluorine and tendons (calf) 

 with 0.0035 p. m. fluorine, are much poorer in fluorine than the bones. 

 The dentin (dog) contains 0.56 p. m. fluorine and the enamel (of a 

 young dog) contained 1.66. p. m. fluorine, all results obtained from the 

 fresh substance. 



AD. CARNOT 2 found the following composition for the bone-ash of 

 man, ox, and elephant: 



Man. Oz. Elephant, 



Calcium phosphate ..................... 874.5 878.7 857.2 900.3 



Magnesium phosphate .................. 15.7 17.5 15.3 19 . 6 



Calcium fluoride ....................... 3.5 3.7 4.5 4.7 



Calcium chloride ....................... 2.3 3.0 3.0 2.0 



Calcium carbonate .................... 101.8 92.3 119.6 72.7 



Iron oxide ............................. 1.0 1.3 1.3 1.5 



The quantity of organic substance in the bones, calculated from the 

 loss of weight in burning, varies between 300 and 520 p. m. This 

 variation may in part be explained by the difficulty in obtaining the 

 bony substance entirely free from water, and partly by the very variable 

 amount of blood-vessels, nerves, marrow, and the like in different bones. 

 The unequal amounts of organic substance found in the compact and 

 in the spongy parts of the same bone, as well as in bones at different 

 periods of development in the same animal, probably depend upon 

 the varying quantities of these above-mentioned tissues. Dentin, which 

 is comparatively pure bony structure, contains only 260-280 p. m. 

 organic substance, and HOPPE-SEYLER 3 therefore thinks it probable 

 that perfectly pure bony substance has a constant composition and 

 contains only about 250 p. m. organic substance. The question whether 

 these substances are chemically combined with the bone-earths or only 

 intimately mixed has not been decided. 



The nutritive fluids which circulate through the bones have not been isolated 

 and we only know that they contain some protein and some NaCl and alkali 

 sulphate. 



1 Compt. Rend., 156. 



2 Ibid., 114. 



* Physiol. Chem., 102-104- 



