OP THE BONES, 367 



bone, is removed from it, and the bone, retaining its form and 

 size, but having lost a part of its weight, equal to that of the 

 earthy matter abstracted, has become flexible and tenacious 

 like the cartilaginiform fibrous tissue. In this state it is re- 

 ducible to glue or gelatin by decoction. In this state also, if 

 it be softened by maceration in water, the compact substance, 

 which presented no apparent texture, divides into laminae, 

 connected together by fibres. The laminae themselves, some- 

 what later, or with more difficulty, divide into fibres, which, 

 by a more prolonged maceration, swell, and become areolar 

 and soft, like the cellular or mucous tissue. 



A long bone, examined by this method, divides at its mid- 

 dle part into several layers, of which the outermost enve- 

 lops the whole bone, and of which the next, becoming thinner 

 towards the extremities, are continuous with the spongy sub- 

 stance with which they are filled. The broad bones are 

 formed of two laminae only, and the short bones of a single 

 lamina which envelops them ; this latter, like the others, 

 presenting at its internal surface filamentous and laminar pro- 

 longations which constitute the spongy substance. 



The bony fibre differs therefore especially from the other 

 animal fibres in the great quantity of earthy substance which 

 it contains. 



In fact, if in place of removing this earthy substance and 

 examining the organic residuum of which we have just spoken, 

 this latter be destroyed, by submitting a bone to the action of 

 fire, there remains a white substance, preserving the volume, 

 form, and a great part of the weight of the bone. This hard, 

 but very fragile substance, is an earthy salt, which forms part 

 of the bony tissue. The other tissues leave, after combustion, 

 a similar residuum or ashes, but in much less proportion, and 

 not preserving, like those of the bones, the form and a part of 

 the solidity of the whole. 



584. The bony fibre is therefore a fibre very similar to 

 the cellular one, but differing from it in the very great quan- 

 tity of earthy substance which enters into its composition. 

 Various ideas have been formed as to the intimate nature of 



this fibre. The opinion most generally admitted consists in 

 48 



