514 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



(7) Add (6) to (2). 



(8) Adjust to a desired pH value by 

 the addition of normal acid or 

 alkali. 



(9) Bring the agar to a boil in the inner 

 compartment of a rice cooker. 



(10) Filter in an autoclave or Arnold 

 sterilizer thru filter paper wetted 

 with boiling water. It may be 

 filtered thru cotton or gauze if 

 clearness of the medium is not an 

 essential. 



(11) Sterilization not specified. 

 (r) Stitt (1923). 



(1) Prepare a paste of 3.0 g. meat ex- 

 tract, 10.0 g. peptone, 5.0 g. NaCl, 

 15.0 g. powdered agar and the 

 white of one egg by mixing with a 

 little water in a mortar. 



(2) Add the remainder of the 1000.0 cc. 

 of water and place in a rice cooker. 



(3) Boil. 



(4) Filter thru absorbent cotton 

 placed between two layers of 

 gauze in a hot funnel. 



(5) Reaction is between +0.7 and 

 +0.8. 



(6) Sterilization not specified. 



(s) Park, Williams and Krumwiede 

 (1924). 



(1) Dissolve, 2.0 to 5.0 g. Beef extract 

 (Liebig's or Armour's), 10.0 g. pep- 

 tone, and 5.0 g. NaCl in 1000.0 cc. 

 water by boiling over a fire. 



(2) Boil 15 minutes. 



(3) Determine the reaction and adjust, 

 if necessary, by the addition of 

 normal NaOH. 



(4) Dissolve 1.5% (or 2.0%) agar in 

 (3) by heating in the autoclave at 

 10 to 15 pounds for 30 minutes or 

 by boiling over the free flame. 



(5) If boiled over a free flame make up 

 the loss in weight by the addition 

 of water. 



(6) Adjust the reaction. 



(7) Cool to 50°C. and add one egg. 



(8) Heat in the autoclave at 10 to 

 15 pounds for 30 minutes, or in an 

 Arnold sterilizer for one hour. 

 Filter. 



(9) Test the reaction and adjust if 

 necessary. 



(10) If more than 0.2% normal soda is 



required per liter, heat again for 

 10 minutes. 



(11) Filter thru cotton. 



(12) Distribute in tubes or flasks. 



(13) Sterilize at 15 pounds pressure for 

 30 minutes. 



References: Heim (1895 p. 193), Ravenel 

 (1899 p. 605), (1899-1900 p. 89), Frost 

 (1903 p. 16), Hesse (1908 p. 441), (1908 

 p. 89), Stokes and Hachtel (1909 p. 40), 

 Viehoever (1913 p. 214), Bengis (1916 

 p. 392), Meier (1918 p. 435), Kligler and 

 Defandorfer (1918 p. 438), Ball (1919 

 p. 80), Tanner (1919 p. 51), Besson (1921 

 p. 43), Giltner (1921 p. 386), Wolf and 

 Shunk (1921 p. 325), Giltner (1921 p. 40), 

 Heinemann (1922 p. 35), Stitt (1923 

 pp. 36, 37), Park, Williams and Krum- 

 wiede (1924 p. 117). 



1695. Heinemann's Meat Extract Agar 



Constituents : 



1. Water (tap) 1000.0 cc. 



2. Agar (1.5%) 15.0 g. 



3. Beef extract 3.0 g. 



4. Peptone, Witte (1.0%) 10.0 g. 



Preparation : 



(1) Weigh accurately a sauce pan with- 

 out the lid. 



(2) Measure 1000.0 cc. of tap water into 

 the pan. Add 300.0 cc. of water to 

 allow for evaporation. Heat over 

 the gas. 



(3) Add 15.0 g. of shredded agar to (2) 

 and boil slowly until solution is 

 complete. 



(4) Add 3.0 g. of beef extract to (3). 



(5) When dissolved remove from the 

 flame and slowly dust in 10.0 g. of 

 Witte's peptone. Stir constantly 

 until dissolved. 



(6) Adjust the reaction to alkaline to 

 litmus or neutralize to phenolphthal- 

 ein and then add 0.5% normal HCl. 



(7) Allow the agar to cool to 60°C. 



(8) Dissolve the whites of two eggs in 

 75.0 cc. of water, and stir well 

 into (7). 



(9) Heat, without stirring, on a piece of 

 asbestos over the flame. 



(10) Make up the weight due to the evap- 

 oration of water, or boil until the 

 proper weight is obtained if the 

 mixture weighs too much. 



