vn CARTILAGE 115 



Thus connective-tissue consists partly of cells, but 

 between these, and forming the main substance of the 

 tissue, is a matrix or intercellular substance, enclosing 

 fibres. In the embryo the tissue consists of closely 

 packed cells, but, as development proceeds, these 

 separate from one another, and the ground-substance 

 is formed between them. 



Cartilage. The ordinary clear or hyaline variety of 

 this tissue is conveniently studied by examining a piece 

 of the thin edge of the omo- or xiphi-sternum, or by 



FIG. 34. Section of cartilage, from the head of the Frog's femur. ( 200.) 

 c. cells ; c'. cells undergoing fission ; c. s. empty cell-space ; in matrix. 



taking a thin section with a razor of the head of the 

 humerus or femur. 



Cartilage consists of a tough, elastic, transparent, 

 homogeneous matrix (Fig. 34, w) containing numerous 

 cavities or cell-spaces (c. s), in each of which is a nucleated 

 cell (c). The cell-spaces, or lacuna, are in many cases 

 arranged in groups of two or four, sometimes close 

 together, sometimes with a narrow space of matrix or 

 intercellular substance between them. This is due to 

 the fact that cartilage grows by the cells undergoing 



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