CARTILAGE. 89 



CHAPTER IV. 



CARTILAGE. 



Articular Cartilage. This is to be studied in 

 sections made both parallel and vertical to the 

 surface. 



Preparation 1. From an animal that has just 

 been killed remove one of the limb-bones, with its 

 articular ends, and with a clean, sharp scalpel or 

 razor take a slice, as thin as possible, off' the carti- 

 lage, and quickly, before it has time to become dry, 

 transfer the piece to a drop of serum upon a slide, 

 place a cover-glass over the preparation and examine 

 with a high power. Turning the attention more 

 particularly to the cartilage-cells, the arrangement 

 of these in groups in the faintly granulous matrix 

 will be noticed. Each cell is seen to be provided 

 with a clear round nucleus, which in some speci- 

 mens of articular cartilage is so large proportion- 

 ately that it may be mistaken by an inexperienced 

 observer for the whole cell. In reality, however, 

 the cell-substance is represented by the clear material 

 (or containing, at most, a few highly refracting 

 granules) which lies around the nucleus and entirely 

 fills the cavity or space in the cartilaginous matrix 

 in which the cell lies. But now replace the serum 

 by distilled water, drawing the former away by 

 means of a piece of blotting-paper placed at one edge 

 of the cover-glass, and allowing a drop of water from 

 a pipette to run under at the opposite edge (see Fig. 

 18), and the picture soon changes. Examine the 

 cells at the borders of the slice, for these are first 

 reached by the water. It will be seen that the clear 

 cell-substance begins to be separated from the matrix, 



b* 



