CARTILAGE AND CONNECTIVE TISSUE. 99 



ing. When a thin slice of hyaline cartilage is examined with 

 a microscope it is found (Fig. 45) to consist of granular nucle- 

 ated cells, often collected into groups of two, four, or more, 

 scattered through a homogeneous or faintly granular ground- 

 substance or matrix. Essentially, cartilage resembles bone, 

 being made up of protoplasmic cells and a proportionately 

 large amount of non-protoplasmic intercellular substance, the 



FIG. 45. A thin slice of cartilage, magnified, to show the cells imbedded in the 

 homogeneous matrix, a, a cell in which the nucleus has divided; 6, a cell in which 

 division is just complete; c, e, a group of four cells resulting from further division 

 of a pair like 6; the new cells have formed some matrix between them, separating 

 them from another; d. d. cavities in the matrix from which cells have dropped out 

 during the preparation of the specimen. 



cells being the more actively living part and the matrix their 

 product. Examples of this hyaline variety (so called from 

 its glassy transparent appearance) are found in all the tempo- 

 rary cartilages, and in the costal and articular among the 

 permanent. 



Cartilages rarely contain blood-vessels except at points 

 where a temporary cartilage is being removed and replaced 

 by bone; then blood-vessels run in from the perichondrium 

 and form loops in the matrix, around which it is absorbed 

 and bony tissue deposited. In consequence of the usual 

 absence of blood-vessels the nutritive processes and exchanges 

 of material must be small and slow in cartilage, as might in- 

 deed be expected from the passive and merely mechanical 

 role which this tissue plays. 



Hyaline cartilage is the type, or most characteristically 

 developed form, of a tissue found with modifications else- 

 where in the Body. One of its other modifications is the so- 

 called cellular cartilage, which consists of the cells with 

 hardly any matrix, only just enough to form a thin capsule 

 around each. This form is that with which all the carti- 



