134 BONE. 



forms ferric phosphate. Pour a few drops from the beaker 

 into a test-tube and test by adding ammonia to see if all 

 the phosphoric acid has united with the iron. If this is 

 the case, the ammonia gives a yellowish precipitate. If 

 not enough ferric chlorid was added the precipitate is 

 white, and more of the iron solution must be added and 

 the test repeated until all the phosphoric acid has been 

 taken by the iron. Then to the solution add a solution 

 of sodium carbonate until it is nearly neutral; that is, 

 until the precipitate which forms as the sodium carbonate 

 strikes the liquid dissolves slowly on stirring. Then 

 add 1 or 2 grammes of barium carbonate to precipitate 

 the ferric phosphate. Filter after warming. Precipitate 

 the barium from the hot filtrate with dilute sulphuric acid 

 and filter. Having thus removed the phosphoric acid, test 

 the filtrate for calcium by making it alkaline with am- 

 monia and adding ammonium oxalate as long as a pre- 

 cipitate is formed. The calcium is thrown down as white 

 calcium oxalate. Filter and to the filtrate add sodium 

 phosphate. A white crystalline precipitate shows mag- 

 nesium. 



302. Test the absorptive power of bone-black by adding 

 it to a light-blue solution of indigo and warming, then filtering. 

 The coloring matter will have almost or entirely disappeared from 

 the filtrate. 



Directions have been given before (Experiment 138) 

 for the separation of the collagen from the mineral con- 

 stituents of the bone. 



MUSCULAR TISSUE. 



A muscle is made up of fibers or cells, consisting of 

 a sheath (the sarcolemma), composed of a substance similar 



