CARTILAGE. 703 



Cartilage forms the entire skeleton in some kinds of 

 fishes, the Skate, Lamprey, &c. In man it is placed 



1 FIG. 333. 2 



1, Cartilage from Rabbit's ear, showing large cells embedded in a fibrous 

 matrix. 2, Cartilage from Human ribs, with cells in groups, each having 

 a granular nucleus. (Magnified 200 diameters.) 



between all the long bones, and also the bones of the 

 vertebral column, there acting as an elastic cushion. 

 Cartilage receives its nourishment 

 by minute blood-vessels. When ex- 

 amined microscopically, the simplest 

 form of cartilage is seen to resemble 

 in a striking manner the cellular 

 tissue of vegetables ; it consists of 

 an aggregation of cells of a spherical 

 or oval form, capable in some cases 

 of being separated from each other, 

 and every cell having a nucleus, 

 with a nucleolus in its interior. In 

 figs. 332, 333, and 334, we have vari- 

 eties of this structure. In the more 

 highly organized scale of animals, 

 a strong fibrous capsule, or sheath, 

 surrounds the cartilage-cells ; some FlG - 3M-Qa>rWage from 



J.T- i T L j_i the Cuttle-fish, showing 



ot the fibres dip in amongst the stellate form of cells. 

 cells, and bind them firmly to- 

 gether. In those inhabitants of the water, the Ray 

 and Shark, the entire skeleton being cartilaginous, 

 the cell is embedded in a matrix, which may 



