COMPOSITION OF BONES. 61 



left in the dish? (This substance is a 

 kind of mineral matter formed from the 

 mineral matter of the bone by the action 

 of the acid.) See experiment 20, B. 

 5. What properties of bone are due to the 

 presence of mineral matter? 



B. Effect of burning bone. 



Weigh half of the long bone used in 30. Tie 

 a piece of wire about it and place it in a hot 

 coal fire. Allow it to remain for a half -hour 

 and then remove it carefully by means of the 

 wire. 



1. Write in your note-book a brief account of 



all the changes which you observed while 

 the bone was in the fire. 



2. Has the bone been changed in form or size? 



3. What change can you see in the bone? 



4. What part of the bone has been most af- 



fected by the fire? 



5. Try to break the bone; what is the use in 



bone of the substance which has been 

 lost? 



6. Weigh the bone and determine what per 



cent, of the original bone remains as ash 

 (mineral matter) and what per cent, has 

 disappeared (animal matter). 



C. Effect of boiling bones in water. 



Place the other half of the soup-bone in a 

 pint of water and allow it to simmer on the 

 back of the stove for 4 to 6 hours. Strain the 

 liquid through a cloth and allow it to cool. 

 I. Describe the substance which is obtained. 



