810 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



(8) Allow the mixture to stand until a 

 gel has formed. 



(9) Place in deep flat vessels and dialyze 

 in running tap water until free from 

 chlorides. This requires about 

 24 hours. 



(10) Transfer the dishes to a sterile vessel 

 containing boiled distilled water. 

 Replace this boiled distilled water 

 several times. 



(11) Dissolve 2, 3, 4 and 5 in 1. 



(12) Grind filter paper. 



(13) Add about 5.0 g. of (12) to (11). 



(14) Pour about 2.0 cc. of (13) over each 

 plate in such a manner so as to have 

 the cellulose evenly distributed over 

 the surface. 



(15) Powder CaCOg on each plate. 



(16) Place the uncovered plates at 65°C. 

 until the excess of water has evap- 

 orated without allowing the plates 

 to become dry. 



(17) Cover the dishes with sterile tops. 

 Sterilization: Method of sterilization of 



(13) not given. 



Use: To cultivate and isolate organisms 

 capable of decomposing cellulose. Cel- 

 lulose decomposing organisms after 48 to 

 72 hours produce yellow or orange colored 

 growth around the soil particles, rapidly 

 spreading over the plate. The yellow 

 organism is Spirochaeta cytophaga. 



Reference: Waksman and Carey (1926 

 p. 90). 



2479. Kiihne's Beef Extract Silicate Jelly 



(Kerry) 



Constituents : 



1. Water 



2. Sodium silicate 300.0 cc. 



3. HCl (dilute) lOO.O cc. 



4. Beef extract (Liebig's) 

 Preparation : 



(1) Mix 3 parts commercial, liquid so- 

 dium silicate (sp. gr. 1.08) with 1 part 

 dilute HCl (l part HCl with sp. gr. 

 1.17 to 1 part water). 



(2) Dialyze in running water 4 days. 

 Then may be dialyzed in distilled 

 water if desired, to remove all NaCl. 



(3) Concentrate the mixture over free 

 flame in a platinum dish. 



(4) Continue to heat until a thin mem- 

 brane is formed. (Liquid has a 



sp. gr. of 1.02 and contains 3.4% 

 pure acid.) 



(5) Mix a piece of Liebig's extract (size 

 of a bean) in 25.0 cc. of water. 



(6) Add 0.5 or 1.0 cc. of (5) to 4.0 cc of 

 (4). (If NaCl be added, solidification 

 will take place more rapidly.) 



Sterilization: It is more satisfactory to 

 sterilize the solutions separately and then 

 mix. In an emergency, however, sterilize 

 the mixture. (Method not given.) 



Use: General culture medium. 



Variants : Sodium chloride or glycerol may 

 be added. 



References: Kuhne (1890 Heft 1) Kerrv 

 (1890 p. 410). 



2480, Omelianski's Gypsum Block 

 Constituents : 



1- Water. 1000.0 cc. 



2. Potassium phosphate 1 g 



3- MgSO, ;. 05g" 



4. (NH,),S04 2.0g." 



5. NaCl oQg 



6. FeSO^ ; o.4g.' 



7. Gypsum 



8. MgCO, 

 Preparation : 



(1) Dissolve 2, 3, 4, 5 and 6 in 1. 



(2) Add MgCOa in excess or the MgCOa 

 may be added to the gypsum block. 



(3) Prepare a completely homogeneous 

 mixture of MgCOs and gypsum using 

 1.0% MgCOs usually. 



(4) Add water to (3), stirring constantly 

 until it reaches the consistency of 

 acid cream. 



(5) Pour on a large piece of plate glass 

 and smooth out to an even thick- 

 ness. 



(6) When solidification starts, make 

 circles (for Petri dishes) or narrow 

 strips (for tubes) . (Circles are made 

 with a Petri dish.) 



(7) When completely solidified, pass a 

 knife between the circles or strips 

 and glass to remove the solid gyp- 

 sum. Equalize the uneven portions 

 as much as possible. 



(8) Place in Petri dishes (or tubes) 

 smooth side up. 



(9) Add (1) to the plate so that the level 

 of solution is half way to the surface 

 of the block. 



