200 SPECIAL MEDIA 



Media for the Study of Plant Bacteria. 



Beetroot. 1 



Carrot. [ are prepared tubes and sterilised in a manner pre- 

 Turnip. [ cisely similar to that described for potato. 

 Parsnip. J 



Hay Infusion. 



1. Weigh out dried hay, 10 grammes, chop it up into fine 

 particles and place in a flask. 



2. Add 1000 c.c. distilled water, heated to 70 C.; close the 

 flask with a solid rubber stopper. 



3. Macerate in a water-bath at 60 C. for three hours. 



4. Replace the stopper by a cotton-wool plug, and heat in 

 the steamer at 100 C. for one hour. 



5. Filter through Swedish filter paper. 



6. Tube, and sterilise as for nutrient bouillon. 



Haricot Bouillon. (For cultivation of bacteria from tubercles of 

 Legumes.) 



1. Measure out 1000 c.c. distilled water into a 2-litre flask. 



2. Weigh out 250 grammes haricot beans and add to the water 

 in the flask. 



3. Weigh out 10 grammes sodium chloride and add to the 

 contents of the flask. 



4. Add i c.c. of a i per cent, solution of sodium bicarbonate. 



5. Place in the steamer at 100 C. for thirty minutes. 



6. Filter. 



7. Weigh out 20 grammes saccharose and add to the filtrate. 



8. Tube, and sterilise as for nutrient bouillon. 



Haricot Agar. 



1. Measure out 400 c.c. distilled water into a "tared" 2-litre 

 flask. 



2. Weigh out 15 grammes agar and mix into a thick paste with 

 too c.c. cold distilled water, and add to the flask. 



3. Dissolve the agar by bubbling live steam through the mixture 

 as in making nutrient agar. 



4. Weigh out 250 grammes haricot beans, place in the flask with 

 the agar mixture. 



5. Add i c.c. of i per cent, aqueous solution sodium bicarbonate. 



6. Weigh out 10 grammes sodium chloride and add to the 

 contents of the flask. 



7. Place in the steamer at 100 C. for thirty minutes. 



8. Adjust the weight of the medium mass to 1030 grammes (the 

 figure per litre obtained experimentally) by the addition of distilled 

 water at 100 C. 



