THE JOINTS. 21 



2. The homogeneous material, or matrix, in which the cells 

 are embedded. Sketch. 



E. The Relation of Cartilage to Bone. 



Materials. A prepared slide of developing bone. Foetal bones 

 of some young animal. (Those of the pig are usually easy to obtain 

 from any butcher.) 



Apparatus. A compound microscope. 



Study : 



1. Some of the long bones of the foetus. 



a. Examine them both in the centre and at the ends. 

 Compare in structure and density. 



b. Compare them in shape with the adult form. 



c. Compare them with cartilage joining the ribs to the 

 breast-bone and with cartilage always present at the joints. 



2. Examine the prepared slide of developing bone. 

 Notice : 



a. The enlargement and rearrangement of cartilage cells. 



b. The calcification of the matrix. 



c. Sketch. 



