24 1 ELEMENTARY BIOLOGY. [XIII. 



a. Large roundish granular cartilage-cells ■will be 

 seen imbedded in a structureless or very finely 

 granular matrix, which is more refractive next 

 the cells than elsewhere, and causes the appear- 

 ance of a sort of halo round each. 



/3. In each cell lies a distinct granular round 

 nucleus or sometimes two nuclei, containins 

 large highly refractive molecules. 



7. If the preparation be carefully made, each cell 

 will at first completely fill the cavity of the 

 matrix in which it lies, but if it be kept some 

 time or be treated with distilled water the cells 

 contract and so leave a transparent ring between 

 their surface and the inside of the cavity in 

 which each lies. 



c. Bone. 



a. Examine a transverse section of hard bone (say 

 a bit of the shaft of the humerus or femur) with 

 1 inch obj. 



a. The Haversian canals: round or oval spaces, 

 usually filled with dirt in grinding down the 

 bone, and therefore black and opaque, but 

 sometimes clear and empty. 



j8. The lamellcB : a series of concentric layers round 

 each Haversian canal. 



7. The lacunce: oval black spots between the 

 lamellae. 



S. The canaliculi : minute black lines seen radlat-; 

 ing from the lacunse, 



