2G8 CARTILAGE. [BOOK I. 



SECT. 3. CARTILAGE. 



structural Cartilage is a tissue composed of certain cells, 



termed cartilage cells, imbedded in a ground substance 

 or matrix. According to the predominating character 

 of this matrix the cartilage may be classified as (1) cellular cartilage, 

 (2) hyaline cartilage, (3) white fibre-cartilage, (4) elastic or spongy 

 cartilage. In the first of these varieties the matrix consists merely 

 of a transparent and very thin envelope termed the capsule, surround- 

 ing each cartilage cell ; these capsules possess the same chemical 

 properties as the matrix of hyaline cartilage ; in the second variety 

 the matrix is composed of a translucent homogeneous substance, 

 which occasionally presents an appearance resembling that of 

 ground glass, and sometimes exhibits fibrillation ; in the third, 

 the cartilage cells are surrounded by capsules which lie imbedded 

 in a preponderating mass of fibres identical with the white fibres of 

 connective tissue ; in the fourth the cartilage cells with their capsules 

 are imbedded in a meshwork of elastic fibres. 



Cartilage The cartilage cell is a mass of protoplasm with one 



cells. or two nuclei, contained in a cavity which it com- 



pletely fills and which is bounded by the so-called capsule of the 

 cartilage cell, this being intercellular substance which is produced 

 by the differentiation of the cell protoplasm. 



It is the capability of producing this intercellular substance which 

 is the very characteristic of the cartilage cell. In cellular cartilage we 

 find an aggregation of cartilage cells, each of which is surrounded by 

 its own capsule : in hyaline cartilage the homogeneous matrix has 

 been produced by the fusion of concentric, and successively developed, 

 cartilage capsules, as can be shewn by subjecting the fully formed 

 and homogeneous tissue to the action of certain reagents, such as a 

 mixture of hydrochloric acid and potassium chlorate, when the 

 appearance of concentric stratification of the matrix, around the 

 cartilage cells, is revealed. 



In young cartilage cells the protoplasm often contains glycogen 

 (C 6 H 10 O 5 ) ; in the cells of the fully developed tissue fat is often 

 seen. 



General Composition of Cartilage. 



Cartilage contains more than half its weight of water, though the 

 proportion varies remarkably. Its solid constituents consist mainly 

 of organic matter with a small proportion of salts, in which sul- 

 phates and phosphates preponderate. 



' The following analyses exhibit the relative proportions of water, 

 organic matters and mineral matters in the cartilage of a young and 

 healthy man (Hoppe-Seyler 1 ) : 



1 Hoppe-Seyler, quoted by Kiihne, Lehrbuch, p. 387. 



