THE CONNECTIVE TISSUES. 



67 



(2) The intercellular substance is abundant in amount and has 

 received the special designation " matrix." According to the char- 

 acter of this matrix, the cartilages have been divided into three 

 varieties : hyaline cartilage, fibro-cartilage, and elastic cartilage. 

 In hyaline cartilage the matrix is clear and homogeneous and has 

 the consistency of gristle. In fibro-cartilage it is traversed by or 

 nearly wholly composed of delicate fibres similar to those of 

 white fibrous tissue, which will be described presently. In elastic 

 cartilage the matrix contains coarse, branching, and anastomosing 

 fibres similar to those of elastic fibrous tissue (vide infra). 



(3) The arrangement of the cells and intercellular substances 

 varies considerably. Sometimes the cells are pretty uniformly 

 distributed throughout the intercellular substance. Sometimes they 



Fig. 50. 



Hyaline cartilage and perichondrium. Human costal cartilage. Same specimen as Fig. 49 . 

 a, group of cells formed by division, but not yet separated by matrix ; b, matrix ; c, cells 

 with a comparatively slight amount of cytoplasm, marking the transition from cartilage 

 to fibrous tissue ; d, perichondrium, composed of fibrous tissue (spindle-shaped cells with 

 a fibrous intercellular substance). 



are arranged in groups of from two to four or even six cells. To- 

 ward the surface of a piece of cartilage the cells are apt to be smaller 

 than those nearer the centre, and are frequently flattened. Here, 

 also, they often lose the characters that distinguish them in the 

 body of the tissue, and more and more closely resemble the cells of 

 the fibrous tissue surrounding the cartilage. This fibrous tissue 

 is called the " perichondrium," and is usually not sharply defined 

 from the cartilage itself, the matrix of the latter becoming more 

 and more fibrous in character and the cells less distinctly like those 



