540 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



(3) Add 15.0 g. glucose. 



(4) Add 12.5 cc. of N/1 soda solution. 



(5) Boil for 30 minutes. 



(6) Allow to slowly solidify. 



(7) Remove from the container in a 

 solid state and cut away the 

 bottom part containing the sedi- 

 ment. 



(8) Melt the clear top portion in a 

 steamer and pour onto a filter. 



(9) Distribute into small test tubes 

 (10 mm. in diameter and 12 cm. 

 high). 



(10) Sterilize two times (method not 

 specified). 



(f) Robinson and Rettger used a medium 

 containing 2.0% opsine, 0.5% NaCl, 

 1.5% agar, 10.0 g. glucose, and 5.0% 

 Liebig's meat extract. 



(g) Dawson studied the variation of B. 

 coll on a medium composed of 2.5 g. 

 peptone, 10.0 g. meat extract, 10.0 g. 

 glucose and 20.0 g. agar (10.0 g. 

 glycerol may be added). 



(h) Stitt prepared the medium as follows: 



(1) Mix 3.0 g. meat extract, 10.0 g. 

 peptone, 5.0 g. NaCl, 10.0 g. glu- 

 cose and 15.0 g. agar with 1000.0 

 cc. water containing the whites of 

 one or two eggs. 



(2) Boil in a rice cooker until solution 

 is complete. 



(3) Filter. 



(4) Sterilization not specified. 

 References: Henneberg (1898 p. 18), Gott- 



heil (1901 p. 432), Bredeman (1909 p. 

 409), Zikes (1911 p. 148), Bachmann 

 (1912-13 p. 7), Burckhardt and Enriquez 

 (1917-18 p. 16), Robinson and Rettger 

 (1918 p. 202), Dawson (1919 p. 142), 

 Stitt (1924 p. 38). 



1755. Oldekop's Neutral Red Glucose 

 Extract Agar 



Constituents : 



1. Distilled water 500.0 cc. 



2. Meat extract (Lie- 

 big's) 5.0 g. 



3. NaCl 2.5 g. 



4. Peptone (Witte sic- 



cum) 10.0 g. 



5. Agar 1.5 g. 



6. Neutral red, concen- 

 trated solution 1.0 or 2.0 cc. 



7. Glucose (0.15%) 0.75 g. 



Preparation : 



(1) Dissolve 2, 3 and 4 in 1. 



(2) Add soda solution until a weak alka- 

 line reaction is obtained. 



(3) Boil one hour and filter. 



(4) Adjust the reaction once more and 

 add 0.3% agar to (3). 



(5) Dissolve the agar by boiling in the 

 autoclave for one hour. 



(6) Filter while hot. 



(7) Add 1.0 or 2.0 cc. of a concentrated 

 neutral red solution (exact con- 

 centration not given). 



(8) Dissolve 0.15% glucose in (7). 



(9) Distribute into 5.0 cc. lots in test 

 tubes. 



Sterilization : Sterilize for 15 minutes to two 

 hours in the autoclave (pressure not 

 specified.) 



Use: Differentiation between coli and ty- 

 phoid organisms. Author reported that 

 coli types produced decolorization and 

 fluorescens after 24 hours. Typhoid 

 colonies caused no change in color of the 

 medium. 



References: Oldekop (1904p. 123), Klimmer 

 (1923 p. 210). 



1756. Bacto Purple Lactose Agar 

 (Dehydrated) 



Constituents: 



1. Distilled water 



2. Beef extract (Bacto) 3.0 g. 



3. Peptone (Bacto) 5.0 g. 



4. Agar (Bacto) 10.0 g. 



5. Lactose (Bacto) 10.0 g. 



6. Dibromcresolsulphonephth- 



alein 0.025 g. 



Preparation : 



(1) Dissolve 29.0 g. of Bacto Purple 

 Lactose Agar (Dehydrated) in 1000.0 

 cc. of distilled water by boiling or 

 autoclaving. 



(2) Restore the loss if necessary. 



(3) If sterilized at 15 pounds pressure for 

 20 minutes, pH = 6.5±. 



Sterilization: Sterilize in the usual manner. 

 Use: To determine lactose fermentation. 



Acid colonies are yellow, alkali producers 



are purple. Author reported that this 



medium is superior to 1757. 

 Reference: Digestive Ferments Co. (1925 



p. 12). 



