OSSIFICATION. 



379 



the fibres have a radiated arrangement, shooting 

 out from the spot where the first deposit took 

 place, as from a common centre. This is seen 

 in Fig. 1 74, which represents the parietal bone of 



the human skull, in an early stage of its ossifi- 

 cation, and shows the radiating fibres very dis- 

 tinctly. In the cubical, and more irregularly 

 shaped bones, the process is, doubtless, con- 

 ducted with the same order and regularity, al- 

 though it cannot so readily be followed by the 

 eye. 



The same process is repeated in different 

 parts of the bone, wherever nature has, in con- 

 formity with determinate laws of developement, 

 appointed particular centres of ossification. The 

 bone continues to extend from each of these cen- 

 tres, proceeding gradually towards the circum- 

 ference, or the remoter parts of the cartilage, on 

 which the ossific materials are moulded, and by 

 the form of which that of the future bone is 

 regulated. The process of ossification has, how- 



