JOINTS AND LIGAMENTS. 151 



lages consist of a homogeneous substance of firm con- 

 sistence, in which there are imbedded a number of 

 groups of cells, each group occupying a cavity lined by 

 a distinct capsule. The temporary, articular, and costal 

 cartilages are of this variety, and all, with the exception 

 of the articular class, are covered by the perichondrium, 

 a fibrous investing membrane in which ramify the 

 nutrient vessels. 



The fibro-cartilages present a blending of the 

 features of the hyaline cartilage with white fibrous 

 tissue; all the interarticular cartilages belong to this 

 class. 



The elastic cartilages consist of a mixture of the 

 hyaline cartilage with yellow elastic fibrous tissue ; they 

 are limited to the larynx and ear. 



Fibrous tissue is of two kinds, white and yellow. 

 The white is very widely distributed and enters into the 

 formation of the various cellular connective tissues and 

 the fasciae, and forms the skeletal structures of the 

 various glands. It consists of bundles of fibres which 

 are disposed parallel one to another ; they do not run in 

 a straight line, but are wavy or undulate in their course. 

 Each bundle is composed of very delicate fibrillse meas- 

 uring -%-Q^-Q-Q to 2"o"g-i5"o nicn i* 1 thickness. A drop of 

 acetic acid placed upon white fibrous tissue causes it to 

 swell up, become indistinct, and lose its physical charac- 

 ters. It is developed from fusiform cells, which closely 

 pack side by side, become elongated, and split up into the 

 fibrillae. 



The yellow fibrous tissue is elastic and consists of 

 twisted, curling fibres from -g-g-^o-g- * TFOT ^ ncn U1 

 thickness. Their genesis is by the stellate connective- 

 tissue corpuscles of Virchow. It is probable that only 

 the polar extremities of these cells change into the yellow 



