150 



PRACTICAL HISTOLOGY. 



[vni. 



of human costal cartilage from an adult. The section becomes 

 uniformly red. Wash it in dilute acetic acid and mount it in 

 Farrant's solution. 



(a.) The cells are more deeply stained than the matrix, and 

 numerous cells will be seen in groups or in rows due to the pro- 

 liferation of cartilage-cells. The cartilage-capsules are usually 

 more deeply stained than the surrounding matrix. Look for a 

 part of the matrix which has become fil>rous. It is deeply stained. 

 If the mirror be slightly tilted, or the light shaded from the pre- 

 paration by the hand, the cartilage- 

 capsules are usually distinctly seen. 



9. Articular Cartilage. Decalcify 

 the head of a long bone (e.fj., the femur) 

 of a cat or other animal in picric acid 

 Hyaline or chromic and nitric acid, with the 

 Cartilage. p rocau tions indicated at p. 37. When 

 it is thoroughly decalcified, make by 

 freezing vertical sections, so as to in- 

 clude the encrusting cartilage and the 

 subjacent cancellous bone. Place some 

 sections in i per cent, osmic acid for 

 twenty-four hours, and stain others in 

 picro-carmine. Mount examples of 

 both in glycerine-jelly, as glycerine or 

 Farrant's solution makes the tissues 

 rather too transparent. 



(a.) (L) Observe the layer of en- 

 crusting cartilage fixed upon the can- 

 cellated bone beneath (fig. 113), a 

 bold, irregular, wavy line separating 

 the cartilage from the bone, but the 

 one dovetails into the other. In the 

 FIG. n 3 . v.s. Articular Cartilage, cartilage notice two areas, an upper and 



Chromic and nitric fluid. Picro- } ,, V. val ; ' mft fwC . 



carmine. ne, \\itn a nyai nx, an< 



a lower, narrower one, with a more 



granular matrix. The latter is the zone of calcified cartilage. A 

 fine wavy delicate line indicates where the hyaline matrix ends and 

 the calcined matrix begins. In the matrix note the cartilage-cells, 

 flattened at the circumference i.e., next the joint cavity in small 

 groups deeper down, and in vertical rows in the substance of the 

 cartilage. 



(/>.) (H) Study the shape of the cells from the free or joint surface 

 downwards. At the circumference they are flattened or fusiform, and 

 deeper down they are more or less polyhedral and arranged in vertical 

 rows. Some of the cells may be somewhat shrunk within their 



Calcified 

 Cartilage. 



Bone. 



