ELASTIC CARTILAGE 



51 



transformed groups of cartilage cells, thus make their appearance 

 within the cartilaginous plates. This fatty metamorphosis is 

 most marked in the elastic variety of cartilage. 



By coloration with iodin, glycogen granules may also be demon- 

 strated in the cartilage-cells (Ranvier *). 



THE PEBICHONDBIITM is a dense fibrous membrane which 

 surrounds each individual plate-like mass of cartilage. It is con- 

 tinuous with the surrounding connective tissue, and is well sup- 

 plied with bloodvessels and lymphatics; it may also contain 

 terminal nerve fibrils. 



The cartilage itself is an absolutely bloodless and nerveless 

 tissue. Neither are lymphatic channels demonstrable within the 

 cartilage matrix. After long maceration or artificial digestion 

 the matrix assumes a granular or fibrous appearance, and small 

 channels have been demonstrated within it, which have been said 

 to connect the various lacunae ; but it is evident that these appear- 

 ances were possibly the re- 

 sult of artificial destructive 

 processes, and could not 

 therefore be considered as 

 evidences of the presence 

 of such structure in living 

 cartilage. 



ELASTIC CARTILAGE 

 (net cartilage, reticular car- 

 tilage) . Elastic cartilage 

 occurs within the human 

 body in the external ear, 

 and in the epiglottis and 

 cartilages of Wrisberg and 

 Santorini in the larynx. 

 It resembles hyaline carti- 

 lage in the presence of 

 large spheroidal cartilage 

 cells and a homogeneous 

 matrix, but the matrix is everywhere permeated by a dense inter- 

 lacing network of fine elastic fibres. These plates of cartilage, 

 like those of the hyaline variety, are surrounded by a dense fibrous 

 perichondrium. Neither blood vessels, nerves, nor lymphatics are 

 distributed within the matrix of elastic cartilage. 



* Traite technique d'histologie, 2 ed., page 235. 



i 



FIG. 53. ELASTIC CARTILAGE FROM THE HUMAN 

 EPIGLOTTIS, SHOWING THE LARGE OVOID CARTI- 

 LAGE CELLS AND THE VERY DELICATE RETICU- 

 LVM OF ELASTIC FIBRES. 



Ehrlich's triacid stain, x 550. 



