CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



515 



(11) Filter thru paper or absorbent cot- 

 ton, using a vacuum pump. 



(12) Tube. 



Sterilization: Sterilize at 120°C. for 5 

 minutes. 



Use: General culture medium. 



Variants : The following methods of prepa- 

 ration have been described by authors 

 indicated: 

 (a) Committee A. P. H. A. (1916). 



(1) Dissolve 3.0 g. Liebig's beef ex- 

 tract and 5.0 g. peptone in 

 1000.0 cc. water by boiling. Make 

 up the loss in weight due to 

 evaporation. 



(2) Filter hot thru paper. 



(3) Add 12.0 g. of oven dried agar, or 

 15.0 g. of market agar, and boil or 

 heat in the autoclave to dissolve. 



(4) Restore the loss in weight due to 

 evaporation. 



(5) If an autoclave is to be used the 

 peptone and beef extract may be 

 added to about 300.0 g. of water 

 and the agar to 700 g. Auto- 

 clave for 15 minutes at 15 pounds 

 pressure. Filter the hot broth 

 thru filter paper and mix the fil- 

 trate with the agar. Filter thru 

 absorbent cotton. 



(6) Adjust the reaction between +0.5 

 and +1.0. 



(7) Cool to 45° and heat to boiling for 

 15 minutes. 



(8) Filter thru paper or absorbent 

 cotton until the medium is clear. 



(9) Tube in 10.0 cc. quantities or dis- 

 tribute in flasks. 



(10) Sterilize at 15 pounds pressure for 

 30 minutes. The medium may be 

 sterilized on 3 successive days for 

 20 minutes after the agar has 

 melted. 



(b) Noyes (1916). 



(1) Dissolve 15.0 g. agar, 10.0 g. pep- 

 tone and 5.0 g. Liebig's extract in 

 1000.0 cc. water. 



(c) Committee A. P. H. A. (1917). 



(1) Add 3.0 g. of beef extract, 5.0 g. of 

 peptone and 12,0 g. of agar, dried 

 for 30 minutes at 105°C. before 

 weighing to 100.0 cc, of water. 



(2) Boil over a water bath until all the 

 agar is dissolved, and then make 

 up the loss by evaporation. 



(3) Cool to 45°C. in a cold water bath, 

 then warm to 65°C. in the same 

 bath without stirring. 



(4) Make up the lost weight, titrate 

 and if the reaction is not already 

 between +0.5 and +1.0 adjust 

 to +1.0. 



(5) Filter thru cloth and cotton until 

 clear. 



(6) Distribute in 10.0 cc. lots in test 

 tubes, or distribute in larger 

 quantities if desired. 



(7) Sterilize in the autoclave at 

 15 pounds (120°C.) for 15 minutes 

 after the pressure reaches 

 15 pounds. 



(d) Committee S. A. B. (1918). 



(1) Prepare according to Committee 

 A. P. H. A. (1916-1917). May be 

 clarified with white of egg. 



(2) Adjust to pH = 6.6 to 7.4. 



(3) Sterilize. 



(e) Tanner (1918). 



(1) Add 3.0 g. beef extract and 5.0 g. 

 peptone to 1000.0 cc. distilled 

 water. 



(2) Heat agar to 105°C. for 30 minutes. 



(3) Weigh out 12.0 g. of (2) and add 

 to (1). 



(4) Boil over a water bath or cook in 

 an autoclave until solution is 

 complete. 



(5) Make up the loss due to evap- 

 oration. 



(6) Cool to 45 or 50°C. and add 10.0 g. 

 of desiccated egg albumin per liter. 



(7) Heat in the autoclave for 30 

 minutes. 



(8) Make up the loss due to evapora- 

 tion. 



(9) Adjust the reaction to +1.0. 



(10) Filter thru cotton or cloth until 

 clear, or centrifuge in a Sharpies 

 centrifuge. 



(11) Tube. 



(12) Sterilize in the autoclave at 120°C. 



(f) Dawson (1919). 



(1) Dissolve 10.0 g, peptone, 10.0 g. 

 meat extract and 20.0 g. agar in 

 1000.0 cc. water. 



(2) Neutralize (indicator not given). 



(3) Sterilization not given. 



(g) Committee A. P. H. A. (1920). 



(1) Same as for 1917, but adjust the 

 reaction to a faint pink with 



