— 34 — 

 Stuil}' under low power, and observe the anastomosing 

 Haversian canals. The bone lamellae and lacunae are 

 arranjxed parallel to them. Sketch under low power. 



(c) Cross-Section of Decalcified Bone. 



A portion of the .sliaft of a small bone was hardened in a 

 saturated aqueous solution of mercuric chloride, docalcitied in 1% 

 liydrochloric acid, stained in Delaiield's iijcmatoxylin. washed in 

 acid alcohol for several hours, dehydrated, embedded in paraffin, 

 and sectioned. Fix to the slide and mount. 



Stud}^ under high power. Observe the Haversian 

 canals ; each contains one or more capillaries or small 

 arterioles in section. The lamellae are arranged around 

 the canals concentrically ; between these are the lacunae ; 

 and in each lacuna a bone cell. The canaliculi are not 

 well shown. The periosteum is composed chiefly of fibrous 

 tissue. On the inner surface of the periosteum will be 

 seen one or more layers of short, irregularly cuboidal cells, 

 the osteoblasts. Sketch under high power. 



(d) Longitudinal Section of Decalcified Bone. 



This was prepared the same as the cross-section. Mount in 

 balsam. 



Study under high power. The Haversian canals and 

 lamellae are seen in longitudinal section ; between two 

 lamellae is a row of lacunas containing bone cells. Sketch 

 as seen under high power. 



