CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



409 



Added nutrients and variants: The author 

 prepared one of the following media, 

 using water and varying amounts of agar 

 as a base: 



(a) 2.5 g. agar and 0.5 g. glucose per 

 1000.0 cc. water. 



(b) 2.0 g. agar and 0.05 g. (NHOaPOj per 

 1000.0 cc. water. 



(c) 5.0 g. agar + 1.0 g. mannitol per 

 1000.0 cc. water. 



(d) 5.0 g. agar + 0.4 g. mannitol per 

 1000.0 cc. water. 



Author used Bacillus gelaticus with 

 Clostridium americanum with (a) and 

 (b), and Bacillus gelaticus with Azoto- 

 bacter chroococcum in solution (c) and (d). 

 Reference: Pringsheim (1910 p. 230). 



1397. Beijerinck's Basal Agar Solution 



(Smith) 



Constituents: 



1. Distilled water. 



2. Agar. 

 Preparation: 



(1) Add ordinary agar to distilled water 

 and heat until solution is complete. 



(2) Pour into Erlenmeyer flasks and 

 allow to solidify. 



(3) When cold, fill the flasks with dis- 

 tilled water and set away. 



(4) Change the water several times, 

 during a lapse of one or two weeks. 



(5) Add any desired inorganic nutrients 

 and some pure precipitated CaCOa. 



Sterilization: Method not given. 



Use: Cultivation of nitrite bacteria. 



Added nutrients: Smith specified the addi- 

 tion of any solution of nutrient salts 

 containing ammonium salts and states 

 that Beijerinck recommended NH4, 

 NaHP04'H20 as the best ammonium 

 salt to be used. 



Reference: Smith (1905 p. 199). 



1398. Ayers, Mudge and Rupp's Washed 



Agar 

 Constituents: 



1. Distilled water 2000.0 cc. 



2. Agar 30.0 g. 



Preparation : 



(1) Place 30.0 g. of shredded agar in a 

 flask with 2000.0 cc. distilled water. 



(2) Allow to stand for 24 hours at room 

 temperature. 



(3) Pour off as much water as possible by 

 placing a piece of cheese cloth over 

 the top of the flask. 



(4) Add fresh distilled water to make up 

 for water poured off. 



(5) Allow to soak for another 24 hours. 



(6) Filter thru a cotton flannel cloth and 

 wash once with a liter of distilled 

 water. 



(7) Allow the agar to drain as much as 

 possible. Press out the remaining 

 water by squeezing the filter cloth 

 with the hands. 



(8) The washed agar may be dissolved 

 in water for the preparation of media 

 or dried in air and used as ordinary 

 agar. In this case use 1.0% of the dry 

 material to obtain a medium having 

 the same jelly strength as a 1.5% 

 shred agar medium. 



Sterilization: Not specified. 



Use : Purified agar. Giltner used a similar 

 medium in the preparation of a solid 

 synthetic medium and for testing food 

 requirements and selective power of 

 bacteria. 



Variants: Giltner used the agar, prepared 

 in the following manner: 



(1) Place 15 parts agar in 1000.0 parts 

 distilled water. 



(2) Cover the mouth of the bottle with 

 parchment paper, or several layers 

 of clean cheese cloth. 



(3) Allow to ferment spontaneously. 



(4) Change the water in the bottle occa- 

 sionally, replacing the amount re- 

 moved with the same amount of 

 clean distilled water. 



(5) When active fermentation has ceased 

 as noted by the evolution of gas 

 place the agar in an agate ware pail. 



(6) Weigh. 



(7) Boil over a free flame to dissolve the 

 agar. 



(8) Make up any loss in weight by the 

 addition of distilled water. 



(9) Distribute as desired. 

 (10) Autoclave. 



References: Ayers, Mudge and Rupp (1923 

 p. 591), Giltner (1921 p. 365). 



1399. Dominikiewicz's Purified Agar 

 Constituents : 



1. Water 200.0 to 400.0 cc. 



2. Agar 30.0 to 40.0 g. 



