CARTILAGES. 289 



reason, cartilages do not readily become atrophied by pres- 

 sure : thus, when an aneurism destroys the bodies of the 

 vertebrae, the intervertebral cartilages are not at the same 

 time removed, but resist for a long period the continued com- 

 pression to which they are subject. 



There is, however, one description of cartilage in which 

 blood vessels regularly appear, viz., cartilages of ossification, 

 in which may be included the costal and thyroid cartilages, 

 their presence proceeding and accompanying the process of 

 the formation of bone. 



Cartilages, like all the extravascular tissues, imbibe fluid 

 readily : thus, when immersed in a coloured solution, they 

 assume the tint of the liquid in which they are placed. In 

 jaundice, according to Bichat *, they present a greenish yellow 

 tint, from the imbibition of a portion of the bile with which, 

 in this disorder, the system is so pregnant. 



GROWTH AND DEVELOPMENT OF CARTILAGES. 



Cartilages, as already observed, consist of cells imbedded in 

 a hyaline or fibrous base. In considering, then, the develop- 

 ment of cartilages, the growth of both the cells and the inter- 

 cellular substance must be discussed. 



We will first describe the multiplication of cartilage cells. 



The Cells. Cartilage cells are multiplied in two ways. 



1st. By the division of a single cell into two or more parts, 

 each of which becomes, when the separation is completely ef- 

 fected, a distinct cell. The reality of this method of increase 

 in the number of cells will become evident on the attentive 

 examination of almost any thin section of cartilage, in the 

 cells of which, but especially in those placed near the 

 natural border, the several stages of their division may be 

 clearly and satisfactorily recognised. (See Plate XXX.) 



2nd. By the development of cytoblasts either in the 

 intercellular substance, or else in parent cells. This mode of 

 increase is a true reproduction, new cells being continually 



* Anat. Gen. t.iii. p. 192. 



