OSSEOUS SYSTEM. 



181 



Q. Is the softer substance plire cartilage or gelatine? 



#. That it is fibrous texture cannot be doubted ; it is 

 neither exclusively cartilage nor gelatine; the phosphate 

 of lime is deposited between these fibrous spaces, and thus 

 constitutes bone. 



Q. What part of the bone possesses vitality and affords 

 nutriment? 



Ji. The gelatinous substance. 



Q. What vessels deposite the calcareous bony matter? 



#. The red blood-vessels. 



Q. Does a different set of vessels deposite the gelatine? 



A. It is poured out by white vessels. 



Q. What is the aspect of osseous vascularity, at different 

 periods of life? 



/2. The vascularity of the bones diminishes with age, 

 and with this diminution of vascularity is a corresponding 

 declension in the readiness to form callus. 



Of the Properties of the Osseous System. 



Q. What are the physical properties? 



#. The bones are extremely solid, and hard ; in the 

 bones of young persons there is slight elasticity, which is 

 entirely lost in advanced life. 



Q. Do the bones possess or exhibit textural properties? 



t#. Bichat supposes that in spina ventosa extensibility 

 of bony texture is manifested ; and this is also exhibited 

 in the distention of the antrum with polypus. On the 

 contrary, the alveoli contract when the teeth are removed; 

 the orbit contracts when a cancerous eye has been re- 

 moved. 



