40 CONNECTIVE TISSUE. 



Fig. 31), where it serves the double purpose of reducing concussion 

 by virtue of its elasticity, and of forming a smooth surface for the 

 motion of the joint. It has no blood-vessels, but is nourished from 

 both the synovial membrane and the bone. It does not ossify 

 that is, become bone. 



Costal Cartilage (Fig. 30). Cartilage of this kind is hyaline, 

 though in old age a fibrous character is observed. Its individual 

 cells are larger, and the groups of them are larger than in articular 

 cartilage. Its tendency to ossify is another difference when com- 

 pared with the articular variety. Ossification and calcification 

 must be very carefully distinguished. In the former a formation 



Cartilage-cell. 



Elastic fibers. 



FIG. 32. Elastic cartilage from the external ear of man : a, fine elastic network in 

 the immediate neighborhood of a capsule ; X 760 (Bohm and Davidoff). 



of bone occurs ; in the latter there is simply a deposition of lime 

 salts. 



Costal cartilage is found in connection with the ribs, and also 

 in the larynx, excepting in those minute structures, the cornicula 

 laryngis or the cartilages of Santorini. It also forms the carti- 

 laginous structure in the trachea, the nose, and the external audi- 

 tory meatus. 



White Fibrous Cartilage or Fibrocartilage (Fig. 31). White 

 fibrous connective tissue, with cartilage-cells between the bundles, 

 characterizes this tissue. It is described as of four kinds, principally 

 by reason of the office it serves ; inter articular, flat plates between 



