26 



LECTUKE U. 



Organic 

 Inorganic 



Goose. 

 Anser (femur.) 



32-91 

 67-09 



BIRDS. 



Turkey. 

 Gallopavo (femur.) 



30-49 

 69-51 



Hawk. 



Falco GaUinarius. 



26-72 

 73-28 



100 00 



100-00 



100-00 



In the above table it will be observed that the bones of the fresh- 

 water fishes are lighter and retain more animal matter than those of 

 the fish which swims in the denser sea, and that the Mammalian 

 marine species, Delphimis, differs little from the sea-fish in this 

 respect. The Batrachian Reptile has more animal matter in its bones 

 than the Ophidian or Saurian, and thus more resembles the Fish. 

 Serpents almost approach Birds in the great proportion of the 

 earthy salts, and hence the density and ivory-like whiteness of 

 their bones. The typical bones of Birds are the whitest and most 

 compact of all bones, by reason of their large proportion of earthy 

 matter, and also of the absence of marrow from their capacious 

 pneumatic cavities, on which their lightness depends : in those bones 

 of Birds from which air is excluded, the oily marrow deadens the 

 whiteness of the tissue, and it is often difficult to get rid of the greasy 

 surface in skeletons. 



The nature of the inorganic or hardening particles, and of the 

 organic basis, according to the analysis by Bibra of completely dried 

 portions of bone, is exemplified in the subjoined table, including a 

 species of each of the four classes of Vertebrata. 



CHEMICAL COMPOSITION OP BONES. 



In addition to the differences already noted in the proportions of 

 earthy and animal matter, it is interesting to observe that the proper- 



