68 SIXTH LECTURE. 



called them osteoblasts— and rightly, for they form the osteoid 

 tissue. 



As in a line of inordinately crowded soldiers, one or 

 another will be pressed out in front, so does it happen to cer- 

 tain of these osteoblasts (g). They now assume indented or 

 stellate shapes ; homogeneous, but very soon diffusely calci- 

 fied intercellular substance then appears around them. The 

 latter as a thin layer — we might say, covering the irregular 

 surfaces of the still remaining calcified cartilage trabecular like 

 a wax impression — is the first lamella of the osteoid sub- 

 stance ; the indented osteoblasts form the first bone cells, 

 however. Our Fig. 6$ shows this at its upper portion 

 (a, a, a), also at the left, half way up (c, d). 



Concerning the conception of the intercellular substance, 

 whether it arises from a secretion ot the cells or from the 

 metamorphosed cell bodies, the same uncertainty of opinion 

 prevails as with other members of the connective substance 

 group. 



We have here still more peculiar illusive appearances to 

 consider. It is comprehended that by the continual lique- 

 faction of the cartilaginous trabecular the cavities of the tissue 

 become opened, and must then serve for the deposition ot 

 bone cells and homogeneous basis substance. When the 

 conditions are as zXf of our Fig. 63, the matter is at once 

 clear, the places is also, in a measure, appreciable. When, 

 however, the cavities are ruptured from below or above, this 

 does not fall within the plane of the section, and we have the 

 deceptive appearance of closed cartilage cavities with endo- 

 genous bone cells. 



This, which thus occurred for the first time, is repeated 

 in rapid sequence manifoldly after each other. Lamella 

 upon lamella with enclosed bone cells result (Fig. 63 in 

 the lower half). We obtain in this way a stratified 

 osteoid tissue. The remains of the cartilaginous tabecular 

 disappear more and more with the continuing process of 

 liquefaction. 



But this thing, in its wild, confused irregularity is very dif- 



