30 BAUR, ON OSSIFICATION OF CARTILAGE, 
the primary and secondary bone-substance is referred to one 
and the same process. 
The share taken by the cartilage-cells in the process of 
ossification, consists im this, that they are the parents of 
those cells which afterward surround the ossifying connective 
substance, and sprout out in a radiate manner to form the 
bone-corpuscles. Thus the cells of the primordial cartilage 
are never, as such, transformed into bone-colls. The num- 
ber, size, and arrangement of the two, are consequently by 
no means the same; it should rather be said, that all the 
bone-corpuscles of a lamellar system correspond to a single 
row of cartilage-cells in the bone. The bone-corpuscles do 
not make their appearance until after the cartilage cells have 
been destroyed in the production of secondary cells, so that 
any transition from one into the other will be sought for in 
vain. 
In sections, on the other hand, taken from slowly and 
imperfectly ossifying cartilage, appearances are not unfre- 
quently met with, showing the occurrence within the still 
visible contours of a cartilage-cell of only one, or of a few 
closely packed bone corpuscles. In this case, the production 
of secondary cells had been limited to a few, or of only one. 
The surrounding of the endogenous cells with ossifying con- 
nective tissue, took place while still within the parent cell; 
true bone-substance, therefore, is limited to the cireumfer- 
ence of the cartilage-cell, whilst the latter itself is surrounded 
by calcified (or, im rachitic boxes, by perfectly hyaline) car- 
tilage-substance. Appearances of this kind have given rise 
to the supposition, that the bone-corpuscles correspond to 
the nuclei of the cartilage-cells, or to the cells themselves, 
thickened by imternal deposit. This view, however, in the 
case of the ossification of fcetal cartilage, leaves us im the 
lurch, whilst the results here obtained permit us to arrive, m 
general, at a satisfactory explanation. The process of ossi- 
fication of the primordial cartilage has shown, on the one 
side, that the bone-substance is not only chemically identical 
with that of connective tissue, but can only be referred, his- 
togenetically, to the elements of that tissue; and, on the 
other, that the tissue of hyaline cartilage is incapable of direct 
ossification, smee it can be shown that neither its substance 
nor its cells, as such, remain in the synonymous elements of 
the bone. The proposition that a formation of bone is pos- 
sible out of cartilage, in the same way as it is out of con- 
nective tissue, by the deposition of calcareous salts in its 
matrix-substance, and the transformation of its morphologi- 
cal elements into bone-corpuscles, is thus contradicted, and, 
