350 



SPECIAL HISTOLOGY. 



Fie. 131. 



stitute a more globular mass. The primordial cells (first 

 parent-cells) during this procedure, sometimes disappear as 

 distinct organisms, owing to the coalescence or fusion of their 

 walls with the interstitial substance, sometimes not ; and the 

 same holds good with those of the subsequent generations. 

 The latter is usually the case in the rounded masses of cells, 

 owing to their smaller size, and around them a contour line 

 may for the most part be recognised, which is nothing more 



than the distended wall of the first 

 / cell; whilst in the rows of cells, the 

 walls of the original cells are not, 

 usually, so merged in the intercellular 

 substance as to escape recognition. 

 The entire matrix, in which the just- 

 described, enlarged, and actively multi- 

 plying cells are enclosed, varies very 

 considerably in thickness in the dif- 

 ferent cartilages ; scanty around the 

 osseous nuclei in the epiphyses and 

 short bones, it is , to l'" thick in the 

 diaphyses. It is universally charac- 

 terised by its yellowish, transparent 

 colour, and its streaky, apparently 

 fibrous fundamental structure, from 

 the other cartilaginous parts, which 

 are, as visual, blueish-white, with a 

 homogeneous or granular interstitial 

 substance. 

 ^ The vessels met wdth in the ossifying 

 cartilages constitute a phenomenon well 

 worth attention ; from the middle of 

 foetal life onwards, they occur in many 

 situations, preceding by a shorter or 

 e longer time the appearance of the 



osseous nuclei, and accompanying their increase. I have ob- 

 served them in the articular cartilage of the epiphyses of the long 

 bones even in a person 18 years old. They entered the cartilage 



Fig. 131. Femur of a child a fortnight old, natural size: a, substantia compact a 

 of the shaft ; b, medullary cavity ; c, substantia spongiosa of the shaft ; d, cartilaginous 

 epiphyses with vascular canals ; e, osseous nucleus in the inferior epiphysis. 



