41 



LESSON XL 



THE CONNECTIVE TISSUES (continued). 



ARTICULAR CARTILAGE. 



1. CUT two or three very thin tangential slices of the fresh cartilage of a joint, 

 mount them in saline solution and examine with a high power. Observe care- 

 fully the form and grouping of the cells. Look at the thin edge of the section 

 for spaces from which the cells have dropped out. Measure two or three 

 cells and their nuclei, and sketch one or two groups. Now replace the saline 

 solution by water and set the preparation aside for a little while. On again 

 examining it, many of the cartilage-cells will be found to have shrunk away 

 from their containing capsules. 



2. Make other sections of the cartilage (1) from near the middle, (2) from 

 near the edge. Mount in magenta solution, and when stained add dilute 

 glycerine and cement the cover-glass. In (2) look for branched cartilage-cells. 

 Draw one or two. 



3. Make vertical sections of articular cartilage from a bone which has 

 been for several days in i per cent, chromic acid solution, and mount the 

 sections in Farrant. Sketch the arrangement of the cells in the different 

 layers. 



4. Wash a fresh joint with distilled water ; drop 1 per cent, nitrate of 

 silver solution over it ; after ten minutes wash away the nitrate of silver 

 and expose in water to the light. When browned, cut thin sections from 

 the surface and mount in Farrant. The cells and cell-spaces show white in 

 the brown ground-substance. Draw. 



Cartilage or gristle is a translucent bluish-white tissue, firm, and 

 at the same time elastic, and for the most part found in connection 

 with bones of the skeleton, most of which are in the embryo at first 

 represented entirely by cartilage. Two chief varieties of cartilage are 

 distinguished. In the one, which is termed hyaline, the matrix or 

 ground-substance is clear, and free from obvious fibres ; in the other, 

 which is termed fibro -cartilage, the matrix is everywhere pervaded by 

 connective-tissue fibres. When these are of the white variety, the 

 tissue is white fibre-cartilage ; when they are elastic fibres, it is yellow 

 or elastic fibro -cartilage. 



Hyaline cartilage occurs principally in two situations namely 

 (1) covering the ends of the bones in the joints, where it is known as 

 articular cartilage; and (2) forming the rib- cartilages, where it is 

 known as costal cartilage. It also forms the cartilages of the nose, the 



