101 OSSEOUS SYSTEM. [sect. 103. 



§ 103. Ossification of the Cartilage. — The ossification of the 

 matrix generally precedes that of the cartilage-cells, and, in normal 

 conditions, is effected b}^ granular precipitates of calcareous salts 

 — the so-called calcareous granules. Wherever rows of cells exist 

 at the ossifying border, these deposits, when viewed in longi- 

 tudinal sections, are seen in the form of pointed processes running 

 into the fibrous substance between the rows, and enveloping the 

 lowermost parts of the latter in form of short tubes. Essentially 

 the same process is seen in other places, where the cartilage-cells 

 are arranged more in the form of rounded groups, except that here 

 the ossifying matrix surrounds the latter more in form of a net- 

 work. If, in microscopical sections, the granules be followed 

 from the border of ossification into the interior of the young 

 bone, it is seen that the latter, although with decreasing dis- 

 tinctness, still exhibits, for a certain distance, the granular and 

 dark appearance of the border itself, then gradually becomes 

 more uniform, clearer and more transparent, and, finally, as- 

 sumes nearly the same appearance as the fully developed bone. 

 To all appearance, the primitive granules gradually coalesce 

 with each other, and thus impregnate the whole tissue of the 

 cartilaginous matrix, instead of only separate parts of it, as at 

 first, and, accordingly, cease to exist, or to be distinguishable as 

 isolated particles. 



With regard to the formation of the lacuna? from the cartilage- 

 cells, there exists a very remarkable difference between rachitic 

 Fig . 85 . bones and normal structures. In rachitic 



bones, as I have shown, the lacunae are 

 formed from the cartilage-capsules by the 

 thickening and ossification of their walls 

 with the contemporaneous formation of 

 canalicular spaces in them ; whilst, at the 

 same time, the primordial utricles, or car- 

 tilage-cells, enclosed by them, are trans- 

 formed into the stellate bone- cells of Virchow, 



Six developing bone-cells from T ,i -n • -\- 1 • n i •■• 



a ricketty bone, as jet sharply In the ossifying diaphysis of a rachitic 



defined from the interstitial sub- 1 ,1 i 1 c ±.\ • l 



stance, a. simple bone-ceiis; bone, the morphology of this process can be 

 to a v^A^^'^^co^t most beautifully observed. If the linearly- 

 £n^ia.%E«&^ o£ arranged, large cartilage-capsules of the 

 meter5 ' ossifying border be followed from without 



inwards, it is soon found that, where the deposition of calcareous 

 salts (which in this case is generally effected without the formation 

 of granules) begins, they exhibit, instead of a membrane indicated 



