OF CARTILAGE. 2!) 



the case in the more completely ossified parts ; there the cell- 

 cavity remains behind, forming a dark indentation in the 

 line, which as it advances renders the tissue transparent, and 

 leaves the cavity a black spot, from which dark fibres, simi- 

 lar to those of the corpuscles of bone, issne in a stellated form. 

 Shortly afterwards the fibres disappear, then the corpuscle gra- 

 dually diminishes, and at last vanishes also, leaving a pale spot. 

 Such an appearance could not be due to an air-bubble in the 

 cell-cavity ; for in that case, I think, the course of its exit 

 might be followed. It is probably a more compact mass of 

 earthy matter, which does not become dissolved so quickly as 

 that contained in the substance of the cartilage. After this 

 has become impregnated with earthy matter, the cell-cavities are 

 also filled, and when so filled they are the osseous corpuscles. 

 Similar observations might be instituted on the ossified carti- 

 lages of mammalia, in which the identity of osseous and carti- 

 lage-corpuscles was rendered more certain by Miescher's re- 

 searches. The next question which presents itself concerns 

 the nature of those minute fibres which proceed in a stel- 

 lated form from the osseous corpuscles. After the earthy mat- 

 ter has been withdrawn the corpuscles may still be seen, though 

 rendered very pale by that process ; the fibres, however, are 

 not at all visible, although a formation corresponding to them 

 is certainly present in the cartilaginous substance, and their 

 extraordinary minuteness sufficiently explains the invisibility. 

 The same formation might also exist before ossification, but 

 be invisible from the like cause. As these fibres and the 

 cell- cavities become filled with earth v matter simultaneouslv, 

 and at a later period than the cartilaginous substance, and 

 since they contain the earthy salts in a more compact and 

 less easily soluble mass, it is probable that they are hollow 

 tubes, that is, canaliculi which proceed from the cell-cavities, 

 spreading out into the cartilaginous substance. According, 

 therefore, to the view which we take respecting the cartilage- 

 corpuscles, according as we consider them to be the cavities of 

 cells, the walls of which have become thickened and blended, not 

 only with one another but with the intercellular substance, so 

 as to form the cartilaginous substance; or as we take them 

 for the entire cells, and the intermediate substance of the 

 cell-cavities as only intercellular substance, so must these tubes 



