L'6» THE HORSE. 



Chemical Composition. — True cartilage contains three fifths 

 of its weight of water. It is ascertained that the cells and the in- 

 termediate substance are composed of diiferent 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 chondrin, 

 which differs from gelatine in not being precipitated by the mine- 

 ral acids. 



FIBROUS TISSUE. 



Fibrous tissue exists very generally throughout the body, 

 being composed of fibres of extreme minuteness. It is found 

 under three forms, as wliite fibrous tissue, yellow fibrous tissue, and 

 red fibrous tissue. 



White fibrous tissue is composed of cylindrical fibres of ex- 

 ceeding minuteness, transparent and undulating. They are col- 

 lected first into small fasciculi and then into larger bundles, which, 

 according to their arrangement, compose thin layers or membranes, 

 ligamentous bands or tendons. The membraneous form is seen in 

 the periosteum and perichondrium, the fasciae covering various 

 organs, the membrane of the brain, &c. — Ligaments are glistening 

 and inelastic bands composed of fasciculi of fibrous tissue generally 

 ranged side by side, sometimes interwoven with each other. These 

 fasciculi are held together by separate fibres, or by areolar tissue. 

 They are of all forms, from the round band to the expanded mem- 

 brane 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, colorless when single, but yellowish when ag- 

 gregated in masses. When this tissue is cut or torn, the fibres 

 become curved at their extremities in a peculiar manner. It is 

 met with in the ligamenta subflava of the vertebrae, the liga- 

 mentum colli, the chordae vocales, and membranes of the larynx and 

 trachea, and the middle coat of the arteries. 



Red fibrous tissue, also called contractile tissue from its pos- 

 sessing the power of contracting under certain stimulants, is inter- 

 mediate between yellow fibrous tissue and muscular fibre. Its 

 fibres are cylindrical, transparent, of a reddish color, and collected 

 in bundles. It has no connection with the joints, but is met with 

 in the iris, around certain excretory ducts, and in the coats of the 

 veins. 



