288 METHODS OF IDENTIFICATION AND STUDY 



5. Add to (b) about 0.5 c.c. ferric chloride solution. 

 Violet colour = phenol. 



(If the distillate be acid the reaction will be nega- 

 tive.) 



6. Add to (c) bromine water. Crystalline white ppt. 

 of tribromo -phenol = phenol. 



NOTE. If both indol and phenol appear to be present in culti- 

 vations of the same organism, it is well to separate them before 

 testing. This may be done in the following manner : 



1. Prepare inosite-free bouillon cultivation, say 200 

 or 300 c.c., in a flask as before. 



2. Render definitely acid by the addition of acetic 

 acid and connect up the flask with a condenser. 



3. Distil over 50 to 70 c.c. 



Distillate will contain both indol and phenol. 



4. Render the distillate strongly alkaline with 

 caustic potash and redistil. 



Distillate will contain indol; residue will contain 

 phenol. 



5. Test the distillate for indol (vide ante). 



6. Saturate the residue, when cold, with carbon 

 dioxide and redistil. 



7. Test this distillate for phenol (vide ante). 



6. Pigment Production. 



1. Prepare tube cultivations upon the various media 

 and incubate under varying conditions as to tempera- 

 ture (at 37 C. and at 20 C.), atmosphere (aerobic and 

 anaerobic), and light (exposure to and protection from) . 



Note the conditions most favorable to pigment 

 formation. 



2. Note the solubility of the pigment in various 

 solvents, such as water (hot and cold), alcohol, ether, 

 chloroform, benzol, carbon bisulphide. 



3. Note the effect of acids and alkalies respectively 

 upon the pigmented cultivation, or upon solutions of 

 the pigment. 



