OF CARTILAGE
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, similar to those of the corpuscles of bone, issue 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 researches. The next question which presents itself concerns
the nature of those minute fibres which proceed in a stellated form from the osseous corpuscles. After the earthy matter has been withdrawn the corpuscles may still be seen, though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 earthy matter simultaneously,
and at a later period than the cartilaginous substance, and
since they contain the earthy salts im 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 cartilagmous 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
