FIBROUS TISSUE 393 



of the joints. In this membrane the blood-vessels which supply the carti- 

 lage with blood, ramify. It is analogous to the periosteum which covers 

 the external surface of bones. 



Nerves. — No nerves have been traced into any of the cartilages ; they 

 are destitute of sensation while free from inflammation. 



Blood-vessels. — Cartilage is non- vascular ; it receives its nourishment 

 from the bone and pez'ichondrium by imbibition. The law of endosmose 

 coming into operation when the tissue is thick, as in the costal cartilages, 

 canals are formed through which the vessels pass to supply the parts 

 which are too far removed from the j)erichondrium. In articular carti- 

 lages no vessels enter. When cai'tilage is removed by mechanical means, 

 or by absorption, it is not regenerated, and when fractured, as in the ribs, 

 there is no reunion by cartilage, but by fibrous, or most frequently by 

 osseous deposition. 



Chemical Composition. — True cartilage contains three-fifths of its weight 

 of water. It is ascertained that the cells and the intermediate substance 

 are composed of different materials. The membranes of the cartilage cells 

 are not resolved by boiling, and offer a lengthened resistance to alkalies 

 and acids. The contents of the cells coagulate in water and dilute acids, 

 and are dissolved by alkalies. The intermediate substance consists of 

 chondrine, which differs from gelatine in not being precipitated by the 

 mineral acids. 



FIBROUS TISSUE 



Fibrous tissue exists very generally throughout the body, being com- 

 posed of fibres of extreme minuteness. It is found under three forms, as 

 white fibrous tissue, yellow fibrous tissue, and red fibrous tissue. 



White fibrous tissue is composed of cylindrical fibres of exceeding 

 iijinuteness, transparent, and undulating. They are collected first into 

 small fasciculi and then into larger bundles, which, according to their 

 arrangement, compose thin layei-s or membranes, ligamentous bands or 

 tendons. The viemhranous form is seen in the periosteum and peri- 

 chondrium, the fascise covering various organs, the membrane of the brain, 

 ■etc. — Ligaments are glistening and inelastic bands, composed of fasciculi of 

 librous tissue genei'ally ranged side by side, sometimes interwoven with each 

 other. These fasciculi are held together by separate fibres, or by ai^eolar 

 tissue. They are of all foi-ms, from the round band to the expanded 

 membx'ane known as a capsular ligament. — Tendons are constructed like 

 ligaments, but usually in larger and more rounded bundles. Sometimes they 

 are spread out in the form of aponeuroses. 



Yellow fibrous tissue is also known as elastic tissue, from its most 

 prominent physical characteristic, in which it differs from white fibrous 

 tissue. It is so elastic that it may be drawn out to double its natural 

 length, without losing its power of returning to its original dimensions. 

 Its fibres are transparent, brittle, flat or polyhedral in shape, colourless 

 when single, but yellowish when aggregated in masses. When this tissue is 

 cut or torn, the fibres become curved at their extremities in a peculiar 

 auanner. It is met with in the ligamenta subflava of the vertebrae, the 



