GENERAL HISTOLOGY. 



103 



tebrates. In its appearance, cartilage is similar to the 

 homogeneous connective substance of many invertebrated 

 animals; the matrix is homogeneous and, at first glance, 

 appears quite structureless (Fig. 41), but, under the action 

 of certain reagents, assumes a fibrous condition. This 

 conduct, as well as the fact that the cartilage grows 

 through changes of the perichondrium, a thin, fibrillar skin 

 covering its surface, makes it more certainly evident that 

 it is homogeneously fibrillar; and it is thereby distin- 



FIG. 40. 



FIG. 41. 



FIG. 40. Tenc'inous tissue. (After Gegenbaur., 



FIG. 41. Cartilage (after Gegenbaur); c, perichondrium; />, transition into typical cartilage (a). 



guished from homogeneous connective substance since it 

 does not, like the latter, designate a lower but a higher 

 stage of tissue formation. In the matrix lie the cartilage 

 cells united in groups and nests, a mode of grouping point- 

 ing to their origin, since each group of cells has arisen from 

 a single mother-cell by successive divisions. In cartilage 

 also, elastic fibres are found ; if present in great number, 

 these change the bluish shiny, liyalinc cartilage into the 

 yellow-colored clastic cartilage. 



Bone is the most complicated structure in the series of 

 connective tissues. It consists of a matrix (ossein), closely 

 allied to glutin, so intimately combined with inorganic con- 



