652 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



(3) Prepare lactalbumin product as 

 follows: 



(a) Heat for 2 to 3 hours 100.0 g. crude 

 commercial milk albumin contain- 

 ing equal amounts of calcium phos- 

 phate and protein, with 200.0 cc. 

 of 10.0% HCl. 



(b) Filter off residue of protein and 

 heat with 200.0 cc. of 10.0% HCl 

 until no Biuret is obtained. 



(c) Heat in open vessel to drive off 

 HCl. 



(d) Neutralize (3) with NaOH and 

 filter. 



(e) Use part of filtrate as such and 

 evaporate rest to paste. 



(4) Dissolve 25.0 g. casein product C, 

 2.5 g. Edestin product, and 2.5 g. lac- 

 talbumin product paste, and 15.0 g. 

 agar in water. 



(5) Make faintly alkaline to litmus. 

 Sterilization: Method not given. 



Use: General culture medium for patho- 

 genic forms. 



Reference: Robinson and Rettger (1918 

 p. 220). 



2031. Robinson and Rettger's Casein 

 Product C Agar 

 Constituents : 



1- Water 1000.0 cc. 



2. Casein product C 30.0 g. 



3. Agar 15.0 g. 



Preparation : 



(1) Boil 50.0 g. of crude casein over a 

 free flame in 200.0 cc. of a 10.0% 

 HCl solution under a reflux condenser 

 for 8 hours. 



(2) Distill the solution by adding water 

 frequently. 



(3) Neutralize the residue by adding 

 NaOH. 



(4) Add 30.0 g. of (3) and 15.0 g. of agar 

 to 1000.0 cc. of water. 



(5) Make slightly alkaline to litmus. 

 Sterilization: Method not given. 



Use: General culture medium for patho- 

 genic forms. 



Reference: Robinson and Rettger (1918 

 p. 220). 



2032. Robinson and Rettger's Casein 

 Product B Agar 

 Constituents: 

 1. Water 1000.0 cc. 



2. Casein product B 15.0 g. 



3. Ag^r 15.0 g. 



Preparation : 



(1) Boil over a free flame 40.0 g. of crude 

 casein with 200.0 cc. of 9.0% HCl 

 under a reflux condenser. 



(2) Heat in an open dish until no more 

 acid vapor comes off. 



(3) Evaporate to a thick paste. This is 

 casein product B. 



(4) Dissolve 15.0 g. of (3) and 15.0 g. of 

 agar in 1000.0 cc. of water. 



(5) Make faintly alkaline to litmus by 

 the addition of litmus. 



Sterilization: Not specified. 

 Use: General culture medium for patho- 

 genic forms. 

 Variants : 



(a) The casein product may be de- 

 colorized with animal charcoal if 

 desired. 



(b) Author added 5.0 g. of Liebig's meat 

 extract with 10.0 g. starch to the 

 medium. 



Reference: Robinson and Rettger (1918 

 p. 220). 



2033. Robinson and Rettger's Edestin 

 Product Agar 



Constituents: 

 1- Water 1000.0 cc. 



2. Edestin product 50.0 g. 



3. Agar 15.0 g. 



Preparation : 



(1) Prepare edestin product as follows: 



(a) Heat over a free flame under a 

 reflux condenser 40.0 g. pure re- 

 crystallized edestin and 10.0% 

 HCl until a Biuret test is no longer 

 given. 



(b) Heat in an open dish to remove as 

 much HCl as possible. 



(c) Decolorize with animal charcoal. 



(2) Dissolve 50.0 g. of (1) and 15.0 g. of 

 agar in 1000.0 cc. of water, 



(3) Neutralize by the addition of NaOH. 

 Sterilization: Method not given. 



Use: General culture medium for patho- 

 genic forms. The addition of meat ex- 

 tract improves the medium. 



Variants: The authors added 5.0 g. Liebig's 

 meat extract to the medium. 



Reference: Robinson and Rettger (1918 

 p. 220). 



