856 
increased if a little acid be added to the sec- 
tion; caustic alkali will produce a similar 
effect. The intercellular tissue having become 
granular, the parietes of the corpuscles next 
undergo a similar change, and the central’ 
nucleus or cavity can no longer be identified. 
The accession of granules to the parietes of the 
corpuscles constitutes the second stage of the 
process of ossification. 
The third stage is an action of a different 
nature, and is fulfilled in the absorption of the 
osseous matter interposed between ‘the cells, 
and also of that portion of the ossified cells 
which lay in contact with the intercellular 
tissue of the columns. 
By this change, the column, once composed 
of closed cells, is converted into a tube marked 
by numerous indentations corresponding in 
number to the cells which entered into its 
formation, there being a contraction at the 
points of junction between the cells. The 
tube so formed, supposing this condition to be 
sarge would eb closed ends, and the 
ength would be determined by the ends of 
the columns of cells from which it was formed. 
(See fig. 462.) 
These elongated tubes, I believe with the 
authors of “The Physiological Anatomy,” to 
be the Haversian canals in their rudimentary 
state. They do not, however, retain this form 
of tubes with closed ends, but like individual 
cells become perforated and communicate 
with other tubes similarly formed ; but as these 
do not follow each other in straight lines, the 
openings are formed at the sides of the tubes 
instead of their ends, so that these commu- 
nications are at angles with the tubes. These 
and other openings which are formed between 
the cells or tubes lying parallel to each other are 
those Haversian canals in their rudimentary 
state which traverse bone at right angles to its 
length, and form anastomoses with the longi- 
tudinal Haversian canals, which in hone are by 
far the most numerous. 
In the tubes no trace is left of the central 
nucleus or cavity of the original cartilage cor- 
puscle; they contain, however, small spheri- 
cal bodies composed of very minute granules. 
These are transparent and resemble in appear- 
ance those peculiar globules found in the blood 
and commonly designated lymph globules. 
(See fig. 462). 
They are very numerous, and, indeed, al- 
most fill the cavity. They have a red tinge, and 
constitute almost entirely the mass of red 
matter found in the interior of all recently 
formed and forming bone. These bodies were 
described by Dr. Todd and Mr. Bowman, and 
they suppose them to be concerned in the 
developement of vessels, since up to this period 
of ossification no bloodvessels exist in the 
forming tissue, but make their appearance so 
soon as the tubes become pervious. 
If a transverse section be made of bone 
in this stage of its formation, there will be 
no difficulty im recognising, first, the ossified 
intercellular tissue, then the ossified parietes 
of the once cartilage corpuscle, which, being 
OSSEOUS TISSUE. 
_ Haversian canal in its ra- (0)) generates: 
now the lining of the tube, will eventually — 
be the external lamina of an Haversian system 5 
and, lastly, the granular globules contained in 
the tubes. vy 
The last point for consideration in the de-_ 
velopement of bone is — 
the formation of the 
hone-cells. Several re- 
cent authors consider 
the cells to be formed 
from the nucleus of th 
cartilage corpuscle; I 
have not been able to 
confirm their state. 
ments, but have bee 
led to entertain a diffe 
rent opimon of the 
origin. The ormati 0 
in of the bok fi of tubes having beer 
dian ts Bb a 
by the eis completed, the inne 
layer formed from the 
parietes of the corpus 
cle is at first thin, ¢ 
a, intercellular tissue 
ossified ; b, ossified pari- 
etes of the corpuscles ; ¢, ( 
granular globules con- could it be withdraws 
tained in the tubes, entire, would look li k 
a tube formed by the junction of a number 
hollow beads. Partial separation mae howeve 
be produced, as seen in fig. 463. This stat 
alternate dilatation and contraction seen int 
tube at its first formation is soon lost, and 
tube becomes of nearly equal diameter throug! 
out from the filling up of the dilatations by t 
deposition of osseous matter in the ust 
nular form. But in this filling up of the di 
tations small cells are left, and these are 
bone-cells in the rudimentary condition, ai 
form the outer layer of cells in the Havers 
system. (See fig. 463.) At first it is diff 
to distinguish the tu 
of the bone-cells , dD 
if a section be ta 
near the perfectedbe 
they will be seen in 
rious stages of di 
lopement. At this 
riod of the forma 
one-cells appear 
the ossified interet 
lar tissue, which | 
the first formed a 
nection between 
systems of tubes, 
which in fully fo 
Section showing the develope- bone unites the 
ment of the bone cells and sian systems. Wit 
the separation that maywe have bone | 
be produced between the perfect state. 
ossified intercolumnar tis- From what ha 
sue and the tissue of the . 
united cells. stated it will be 
a, ossified intercolumnar that the cartilage 
tissue ; 5, ossified parietes corpuscle is the 
of the united cells; c¢, the part formed ;_ tha 
dimentary state; d, bone Be: 
cells in their first stage of that Be , pg 
developement. lining ©} the p 
tube; that the 
becomes the external lamina of an Hav 
system: so that the parietes of the « 
5 
