1 86 SPECIAL MEDIA 



to complete the solution of the peptone, and filter into a clean 

 flask. 



5. Fill into tubes in quantities of 10 c.c. each. , 



6. Add to each tube o.i c.c. of a 2 per cent, neutral solution 

 of ferric tartrate. (A yellowish-white precipitate forms.) 



7. Sterilise as for nutrient bouillon. 



Lead Peptone Solution. 



Prepare as for iron peptone solution but in step 6 substitute 

 o.i c.c. of a i per cent, neutral aqueous solution of lead acetate. 



Nitrate Peptone Solution (Pakes). 



1. Weigh out Witte's peptone, 10 grammes, and emulsify it 

 with 200 c.c. ammonia-free distilled water previously heated to 

 60 C. 



2. Wash the emulsion into a flask and make up to 1000 c.c., 

 with ammonia-free distilled water. 



3. Heat in the steamer at 100 C. for twenty minutes. 



4. Weigh out sodium nitrate, i gramme, and dissolve in the 

 contents of the flask. 



5. Filter through Swedish filter paper. 



6. Tube, and sterilise as for nutrient bouillon. 



Litmus Bouillon. 



1. Measure out nutrient bouillon, 1000 c.c. (vide page 163, 

 sections i to 6). 



2. Add sufficient sterile litmus solution to tint the medium a 

 dark lavender colour. (Media rendered + 10 will usually react 

 very faintly alkaline or occasionally neutral to litmus.) 



3. Tube, and sterilise as for bouillon. 



Rosolic Acid Peptone Solution. 



1 . Weigh out rosolic acid (corallin) ,0.5 gramme, and dissolve 

 it in 80 per cent, alcohol, 100 c.c. Keep this as a stock solution. 



2. Measure out peptone water (Dunham), 100 c.c., and rosolic 

 acid solution, 2 c.c., and mix. 



3. Heat in the steamer at 100 C. for thirty minutes. 



4. Filter through Swedish filter paper. 



5. Tube, and sterilise as for nutrient bouillon. 



Capaldi=Proskauer Medium, No. I. 



i. Weigh out and mix 



Sodium chloride 2.0 grammes 



Magnesium sulphate o.i gramme 



Calcium chloride 0.2 gramme 



Monopotassium phosphate ....2.0 grammes 



a. Dissolve in water 1000 c.c. in a 2 -litre flask 



