BONE 159 



Wash the specimen thoroughly in water ; stain with carmine, 

 a/nd mount as a permanent preparation in glycerine ; examine 

 with the high power, and note tliat 



iii. The cell nuclei are stained deeply, and the matrix 

 very slightly ; the layer of matrix immediately 

 surrounding each cell — the capsule — stains more 

 deeply than the other parts. 



b. Articular cartilage. This forms caps covering the 

 ends of those bones which fit together to form mov- 

 able joints ; the caps act as elastic cushions to break 

 the force of shocks. 



Mount in balsam a prepared section of articular cartilage from 

 the head of the femur, tlie section being made perpendicular to the 

 articular surface ; examine with low aiid high powers. 

 i. The matrix is hyaline or faintly granular. 



ii. The cartilage cells. Towards the free surface the 

 cells and cell groups become gradually flattened, 

 and arranged parallel to the surface. 



F. Bone. 



Bone consists of a dense fibrillar intercellular matrix, in 

 which are imbedded cells which lie in cavities connected with 

 one another by fine branching canals. The matrix is richly 

 impregnated with inorganic salts, chiefly phosphate and car- 

 bonate of lime, which form about two-thirds by weight of the 

 substance of the bone, and give it its great hardness and 

 strength. The matrix, with its contained bone-cells, is arranged 

 in concentric layers or lamellae, around tubular passages, the 

 Haversian canals, in which lie the bloodvessels, which pene- 

 trate the bone in great numbers. A Haversian canal with its 

 contained bloodvessels, and its surrounding layers of matrix 

 and cells, are together spoken of as a Haversian system. 



1. Examine with both low and high powers prepared trans- 

 verse sections of a long bone. 



i. The Haversian systems form the greater part of 

 the bone, and are readily recognised by the con- 

 centric arrangement of the lamellae, and the 

 central canals. 



