MINUTE STRUCTURE OF BONE. 



353 



circles, Lamellae, around the haversian canals, somewhat like 

 the rings seen on the end of a log. 



Between the rings are circles of elongated dark dots. 

 These are Lacunas, cavities in which lay the bone corpuscles 



Lamellc 



Lacunae 



t\ A 



Canalicul 



Fig. 103. Cross Section of Bone. 

 (Highly Magnified.) 



Haversian Canal 



which built up the bone. The bone was, at first, cartilage. 

 Later, mineral matter was deposited forming true bone. 



3. Now examine the section under a one-fifth-inch objec- 

 tive. From the lacunse there run out, in every direction, 

 little crevices, appearing as fine black lines. These are the 

 Canaliculi. Through the haversian canals, lacunse, and cana- 



