ELASTIC AND WHITE FIBRO-CARTILAGE 41 



The intercellular substance of hyaline cartilage, when viewed fresh or 

 after ordinary fixation, appears homogeneous. However, when subjected 

 to special methods, the seemingly homogeneous intercellular substance can 

 be shown to be made up of fibers, comparable with those found in white 

 fibrous tissue, embedded in the homogeneous matrix. 



In the hyaline cartilage of the ribs the cells are mostly larger than in 

 the articular variety, and there is a tendency to the development of fibers 



FIG. 50. Yellow Elastic Cartilage of the 

 Ear. Highly magnified. (Hertwig.) 



FIG. 51. White Fibro-cartilage. 

 (Cadiat.) 



in the matrix, figure 49. The costal cartilages also frequently become 

 calcified in old age, as also do some of those of the larynx. 



In the fetus cartilage is the material of which the bones are first con- 

 structed; the " model" of each bone being laid down, so to speak, in this 

 substance. In such cases the cartilage is termed temporary. It closely 

 resembles the ordinary hyaline cartilage, but the cells are more uniformly 

 distributed throughout the matrix. 



Elastic and White Fibro-cartilage. The first variety is found in 

 the cartilage of the external ear; the latter in portions of the joints, the inter- 

 vertebral cartilages, etc. 



Structure. Elastic and white fibro-cartilage are composed of cells and a 

 matrix; the latter being made up almost entirely of fibers closely resembling 

 those of fibrous connective tissue. 



Development of Cartilage. Cartilage is developed out of mesoblast cells 

 with a very small quantity of intercellular substance. The cells multiply by 

 fission within the cell capsules. 



