44 VETERINARY PHYSIOLOGY 



capsule which expands the original capsule of the mother 

 cell, and thus increases the amount of the formed material. 

 This formed material has a homogeneous, translucent 

 appearance, and a tough and elastic consistence, and cuts 

 like cheese with the knife (fig. 12). 



The formed material of cartilage, chondro -mucoid, is not 

 a special substance, but a mixture of chondroitin-sulphuric 

 acid with collagen in combination with proteins. Chondroitin, 

 when decomposed, yields glucosamine, a sugar-like substance 

 containing nitrogen (p. 35) ; glyciironic acid, a sugar with 

 the terminal carbon oxidised to the carboxyl state ; and 

 acetic acid probably derived from the amino-acetic acid 

 of collagen. 



Cartilage is surrounded by a fibrous membrane, the peri- 

 chondrium, and frequently no hard-and-fast line of demarca- 

 tion can be made out between them. The fibrous tissue 

 ijraduallv becomes less fibrillated, the cells become less 

 elongated and more oval and the interfibrillar substance 

 increases in amount and becomes of the same refractive 

 ._„.™. , ,,,^^.^^__,_^„-. -..„-,. index as the fibres. During 



old age, a fibrillation of 

 the honiocfeneous - lookincr 

 cartilage is made manifest, 

 especially in costal cartilage, 

 by the deposition of lime 

 salts in the matrix, between 

 the fibres. It was long ago 

 shown that in inflanmiation of 

 cartilage this fibrillation 

 appears ; and by digesting 



..,^-j»"g^v. 



kZ-«^ 



m 



- «•<■ , 



y -i\ L.' it in baryta water, a similar 



■ ' • ^ ■■^' '■'-' 'SMMMMMB Structure may be brought 



Fig. 12.-Hyaline Cartilage covered ^^^^_ rpj^^ ^j^^^ connection 

 by pericnonanuni. 



of cartilage with fibrous 

 tissue is thus clearly demonstrated. 



Such homogeneous hyaline cartilage precedes most of the 

 bones in the embryo, and covers the ends of the long bones 

 in the adult (articular cartilage), forms the framework of 

 the larynx and trachea and constitutes the costal cartilages. 



