General Bacteriology. 67 



EXERCISE LXI. SEPARATION OF BACTERIAL COLORING HATTER. 



a. Make four agar streaks of Bacillus prodigiosus, which are to be kept in the dark 

 until the coloring matter is well formed. 



b. Add about 10 cc. of ether to each tube and shake vigorously until the red pig- 

 ment has all been dissolved out. 



c. Pour into a large test-tube and allow to stand over night in the dark, then 

 pipette off the colored portion. 



d. Divide this into four parts and treat them as follows: 



1. Evaporate on glass slide and examine crystals formed under microscope. 



2. Add a few drops of hydrochloric acid, drop by drop. 



3. Add a few drops of sodium hydroxide. 



4. Stand in 'direct sunlight. 



