Chap, vi.] CARTILAGE. 45 



a network of branched cells ; but in the adult state 

 the reticulum itself possesses no nuclei. Those found on 

 it do not form an essential part of it. 



(2) The neuroglia of Virchow is a dense network 

 of very fine homogeneous fibrils forming the support- 

 ing tissue for the nervous elements in the central 

 nervous system. These fibrils are supposed to be 

 elastic fibres (Gerlach). Embedded in the network of 

 these fibres are found branched nucleated flattened 

 cell plates, which are the proper connective tissue cells. 



(3) Gelatinous tissue. This occurs chiefly in 

 the embryo, being the unripe state of fibrous 

 connective tissue. It consists of spindle-shaped or 

 branched connective tissue cells, separated from one 

 another by a homogeneous transparent mucoid sub- 

 stance. It is met with in the umbilical cord of the 

 embryo, and in the places where fibrous connective 

 tissue is to be developed. After birth it is found in 

 the tissue of the pulp of the teeth, and in the cavity 

 of the middle ear, and in some places as precursor 

 of fat tissue. 



CHAPTER YI. 



CARTILAGE. 



54. Cartilage consists of a firm ground substance 

 which yields ckondrin, and of cells embedded in it. 

 Most cartilages (except on the articulation surface) 

 are covered on their free surface with a membrane of 

 fibrous connective tissue with a few elastic fibrils. 

 This membrane is supplied with blood-vessels, lym- 

 phatics, and nerves, and is of essential importance for 

 the life and growth of the cartilage v This is the peri- 

 chondrium. There are three varieties of cartilage. 



