188 



DETAILED SYNTHESIS. 



186. BOXY TISSUE is ALSO CONSTRUCTED in very 

 dense laminae, as at the surface of the bones, or in a 

 cancellated manner, as at the ends of all and in the cen- 

 tres of many, or with large central canals, as in the long 

 bones in all of which spaces marrow is deposited. 



FIG. 152. 



Fig. 152 represents a portion of bone beneath a portion of cartilage, 

 attached and forming the surface of a joint. The cells in it are, near the 

 bone, perpendicular to it, and near the surface parallel to it. The bone 

 appears in laminae, with numerous lacunae and several Haversian canals, 

 7, in their midst. 



Fig. 153 represents a portion of fibro-cartilage ; a, more highlj magni- 

 fied, and bone, b, the configuration of the laminae being indicated, and the 

 lacunae, in black, irregular spots, with their canaliculi radiating from them, 

 being very distinctly shown. These are cavities. 



187. THE BONY TISSUE is also deposited around 

 minute canals, called Haversian, after their first describ- 

 er, and around small cavities called lacunae, that are ex- 

 ceedingly numerous ; so that though Bony Tissue may 

 seem to be very dense, it will be found to be excavated 



186. How ? Describe Fig. 152. Describe Fig. 153. 187. how depoeited? 

 Is the bony tissue really dense ? 



