BONE. 529 



such as marrow, blood-vessels, etc., which they contain. The same 

 reason explains, to all appearances, the larger quantity of organic 

 substance in the spongy part of the bones as compared with the more 

 compact parts. SCHRODT l has made comparative analyses of different 

 parts of the skeleton of the same animal (dog) and has found an essential 

 difference. The quantity of water in the fresh bones varies between 

 138 and 443 p. m. The bones of the extremities and the skull contain 

 138-222, the vertebrae 168-443, and the ribs 324-356 p. m. water. The 

 quantity of fat varies between 13 and 269 p. m. The largest amount 

 of fat, 256-269 p. m., is found in the long tubular bones, while only 

 13-175 p. m. fat is found in the small short bones. The quantity of 

 organic substance, calculated from fresh bones, was 150-300 p. m., and 

 the quantity of mineral substances 290-563' p. m. Contrary to the 

 general supposition the greatest amount of bone-earths was not found 

 in the femur, but in the first three cervical vertebrae. In birds the 

 tubular bones are richer in mineral substances than the flat bones 

 (DURING), and the greatest quantity of mineral bodies has been found 

 in the humerus (HILLER, DURING 2 ). 



We do not possess trustworthy information in regard to the compo- 

 sition of bones at different ages. The analyses by E. VOIT of bones of 

 dogs, and by BRUBACHER of bones of children, apparently indicate that 

 the skeleton becomes poorer in water and richer in ash with increase 

 in age. GRAFFENBERGER 3 has found in rabbits, 6J-7J years old, that 

 the bones contained only 140-170 p. m. water, while the bones of the 

 full-grown rabbit 2-4 years old contained 200-240 p. m. The bones of 

 old rabbits contain more carbon dioxide and less calcium phosphate. 



The composition of bones of animals of different species is but little known. 

 The bones f birds contain, as a rule, somewhat more water than those of mam- 

 malia, and the bones of fishes contain the largest quantity of water. The bones 

 of fishes and amphibians contain a greater amount of organic substance. The 

 bones of pachyderms and cetaceans contain a large proportion of calcium carbo- 

 nate; those of granivorous birds always contain silicic acid. The bone-ash of 

 amphibians and fishes contains sodium sulphate. The bones of fishes seem to 

 contain more soluble salts than the bones of other animals. 



A great many experiments have been made to determine the exchange 

 of material in the bones for instance, with food rich in lime and with 

 food deficient in lime but the results have always been doubtful or 

 contradictory. The attempts to substitute other alkaline earths or 

 alumina for the lime of the bones have also given conflicting results. 4 



1 Cited from Maly's Jahresber., 6. 



2 Killer, cited from Maly's Jahresber., 14; During, Zeitschr. f. physiol. Chem., 23. 

 Volt, Zeitschr. f. Biologic, 16; Brubacher, ibid., 27; Graffenberger in Maly's 



Jahresber., 21. 



4 See H. Weiske, Zeitschr. f. Biologie, 31, and W. Stoeltzner, Pfliiger's Arch., 122, 

 and H. Stoeltzner, Bioch. Zeitschr., 12. 



