14 



HISTOLOGY. 



Fig. 15. Elastic tissue 

 (from Martin). 



fat (adipose tissue) by the deposition of oil in the protoplasm 

 of the cells. In elastic tissue (yellow 

 connective tissue) the intercellular fibres 

 are larger, and elastic in character. 



In cartilage the intercellular sub- 

 stance (here called the matrix) is more 

 solid and firmer. It varies considerably 

 in abundance, and in proportion to its 

 amount the cartUage gains as a support- 

 ing tissue. When the matrix is homo- 

 geneous, the result is hyaline cartilage ; 

 but it may be traversed by fibres of 

 white or yellow connective tissue, thus 

 producing fibrous or elastic cartilage. 

 The cells of cartilage are circular, oval, 

 or fusiform in outline ; but they send out 

 very fine protoplasmic processes which 

 traverse the matrix, thus connecting all parts. Cartilage in- 

 creases in size in three ways, — by addition of new cells to the 

 outside, by increase in the amount of the matrix, and by division 

 of the cells in the cartilage 

 itself. In almost ever}' sec- 

 tion of cartilage several gen- 

 erations of cells may be 

 readily traced by observing 

 the capsules surrounding 

 them. Cartilage is very 

 closely related to bone, and 

 is frequently converted into 

 that more solid substance by 

 a change (ossification) in its 

 matrix. Cartilage ma\' also 

 be calcified by the deposition 

 of lime upon its surface. 

 Calcified cartilage and bone are entirely distinct. 



In bone this matrix consists of an organic basis combined 

 with salts of lime (chiefly carbonate and phosphate) ; while car- 

 tilage is usually solid, bone is traversed by tubes (Haversian 



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 ^^^ 





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Fig. 16. Hyaline cartilage, the 

 matrix dotted. 



