338 



PHYSIOLOGY, 



3. Examine with a High Power. Now examine the section 

 under a one-fifth-inch objective. From the lacunae there run out, in 

 every direction, little crevices, appearing as fine black lines. These 

 are the canaliculi. Through the haversian canals, lacunae, and cana- 

 liculi, the nourishing materials of the blood reach all parts of the bone. 



The Chemical Composition of Bone. i . Take a tall, narrow 

 glass jar, called in the chemical laboratory a "graduate," or a lamp 

 chimney corked at one end answers very well, and nearly fill with 



Lamellae Lacunae 



A A 

 'f\ A 



Canaliculi Haversian Canal 



Fig. 106. Cross-section of Bone. (Highly Magnified.) 



water. Add one sixth as much hydrochloric acid. Put into this a 

 slender, dry bone, such as a fibula or rib. In twenty-four hours take it 

 out, rinse it thoroughly, and examine it. The acid will probably have 

 dissolved out the mineral matter and left the animal matter. 



2. Lay a piece of bone on a shovel, or piece of sheet iron, and place 

 in the fire. The animal matter is burned out, leaving the brittle min- 

 eral matter. 



