CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



591 



(5) Add 5, 6 and 7 to (4). 



(6) Boil over saturated solution of NaCl 

 in a double boiler for 45 minutes. 



(7) Strain thru absorbent cotton. 



(8) Titrate to pH = 7.3. 



(9) Tube. 



Sterilization: Sterilize in autoclave for 20 

 minutes. 



Use: To maintain cultures of gonococci. 

 Authors reported that growth started as a 

 film on the surface and radiated from 

 point of inoculation. The gonococci 

 survived on this medium for from 3 to 4 

 weeks. 



Reference: Kinsella, Brown and Garcia 

 (1923 p. 4). 



1879. Ayers and Johnson's Casein Gelatin 

 Agar 



Constituents : 



1. Distilled water 500.0 cc. 



2. Meat infusion broth 500.0 cc. 



3. Peptone (Parke-Davis) 10.0 g. 



4. Gelatin (Difco) 10.0 g. 



5. Casein (pure, prepared ac- 

 cording to Hammarsten) 5.0 g. 



6. Glucose 0.5 g. 



7. Na2HP04-2H20 (Sorrenson's 

 phosphate) 4.0 g. 



8. Sodium citrate 3.0 g. 



9. Agar 7.5 g. 



Preparation : 



(1) Prepare meat infusion broth. 



(2) Add 10.0 g. peptone (Parke-Davis) 

 and 2.0 g. Na2HP04-2H20 (Sor- 

 renson's phosphate.) Heat until 

 solution takes place. 



(3) Adjust the reaction to pH = 7.8. 



(4) Dissolve 5.0 g. pure casein (prepared 

 according to Hammarsten) and 2.0 g, 

 Na2HP04-2H20 (Sorrenson's phos- 

 phate) in 150.0 cc. distilled water by 

 heating. 



(5) Mix (4) and (3). 



(6) Add 10.0 g. of gelatin (Difco) to (5). 



(7) Heat (6) in the autoclave at 15 

 pounds for 10 minutes. 



(8) Add 0.5 g. glucose. 



(9) Reaction should be pH = 7.6. 



(10) Filter thru paper. 



(11) Prepare 250.0 cc. of 3.0% agar (Not 

 specified if the agar is to be dissolved 

 in meat infusion or water). 



(12) Filter (11) thru cotton and dissolve 



3.0 g. of sodium citrate in the melted 

 agar. 



(13) Mix (12) and (10) and make up to 

 1000.0 cc. by adding distilled water. 



(14) Tube. 



(15) Final pH = 7.5. 



Sterilization: Sterilize for 20 minutes at 15 

 pounds in the autoclave. (A precipitate 

 may be formed. It will settle out or be 

 absorbed in a short time. In either case 

 the medium is not effected). 



Use: To carry stock cultures of strepto- 

 cocci, DipJococcus pneumoniae, Hemo- 

 philus pertussis, Pasteurella bovis, Ery- 

 sipelothrix porci. 



Reference: Ayares and Johnson (1924 p. 

 112). 



1880. Frazier's Gelatin Agar 



Constituents : 



1. Distilled water. 



2. NaCl 



3. KH2PO4 



4. K2HPO4 



5. Gelatin Bacto.. 



6. Peptone Bacto. 



7. Glucose. . . ; 



8. Beef infusion 



1000.0 cc. 



5.0 g. 



0.5 g. 



1.5 g. 



4.0 g. 



0.1 g. 



0.05 g. 



5.0 cc. 



9. Agar (3.0%) 15.0 g. 



Preparation: 



(1) Dissolve 2, 3 and 4 in 100.0 cc. distilled 

 water. 



(2) Dissolve 4.0 g. Bacto gelatin in 

 400.0 cc. distilled water and add 0.05 

 g. glucose, 0.1 g. Bacto peptone, and 

 5.0 cc. of beef infusion. 



(3) Mix (1) and (2) and heat in a steamer. 



(4) Prepare 500.0 cc. of a 3.0% washed 

 agar. 



(5) Mix (4) and hot (3). 



(6) Adjust to pH = 7.0. 



(7) Tube or flask. 



Sterilization: Sterilize in the autoclave. 



Use: To determine gelatin decomposition. 

 Pour plates of the medium, allow to 

 harden, inoculate duplicate plates, on the 

 surface of the medium, so as to form a 

 giant colony. Following incubation for 

 2 or 3 days, flood one plate with a 1.0%, 

 solution of tannic acid while the duplicate 

 plate is flooded with an acid solution of 

 bichloride of mercury, (HgCl2 15.0 g., 

 HCl (con.) 20.0 cc. and water 100.0 cc). 

 If the gelatin has been attacked, a clear 



