CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



325 



(10) Transfer to a Winchester quart and 

 wash out the mixing vessel with a 

 liter of cold tap water. Add this 

 wash water to the casein solution. 



(11) Cool to 40°C. and add 50.0 cc. of (7) 

 and 15.0 cc. of chloroform. 



(12) Shake well, stopper with a loose cork, 

 and incubate at 37° to 40°C. Shake 

 the bottle each day to break up 

 lumps. 



(13) Add 50.0 cc. more of (7) after 5 days 

 and allow to stand for 10 more days. 

 The material is digested 15 days in 

 all. 



(14) Shake well and transfer to a large 

 3 liter flask, add 400.0 cc. of normal 

 HCl (or 40.0 cc. of pure concen- 

 trated HCl diluted with 360.0 cc. 

 water) . Shake, steam for 30 minutes 

 and filter. 



(15) Add 120.0 cc. of normal NaOH. 



(16) Adjust to pH = 7.35. 



(17) This is a stock broth solution. 



(18) To prepare tryptic broth dilute (17) 

 with twice its volume of 0.5% NaCl. 

 Adjust the reaction to pH = 7.35. 



Sterilization: Sterilize on 3 consecutive 

 days rather than in the autoclave. 

 (Details not given.) 



Use: Substitute for peptone. General cul- 

 ture medium. 



Variants: The author dissolved 2.0 g. of 

 glucose or dulcitol in 40.0 cc. of a 0.04% 

 phenol-sulphone-phthalein solution in a 

 liter of the medium as prepared above. 

 The medium was tubed in 3.0 cc. quanti- 

 ties and sterilized in steam on each of 3 

 successive days for 20 minutes each day. 



Reference: Cole and Onslow (1916 pp. 10, 

 1012). 



1131. Berman and Rettger's Trypsinized 

 Casein Solution 



Constituents: 



1. Water 1000.0 cc. 



2. Casein 



3. Beef extract 2.5 g. 



4. NaCl 5.0 g. 



Preparation : 



(1) Digest a solution of casein with com- 

 mercial trypsin at 45°C. for several 

 hours. 



(2) Dissolve 2.5 g. beef extract and 5.0 g. 

 NaCl in 1000.0 cc. of (1). 



Sterilization: Method not given. 

 Use: To study bacterial nutrition. 

 Reference: Berman and Rettger (1918 

 pp. 383, 384). 



1132. Norris' Trypsinized Caselnogen 

 Solution 

 Constituents : 



1. Water 1000.0 cc. 



2. Caseinogen 100.0 g. 



Preparation : 



(1) Digest 100.0 g. (10.0%) caseinogen in 

 an 0.8% aqueous solution of washing 

 soda with a 0.5% pancreatic extract 

 at 37 °C. for 24 hours. 



(2) Concentrate the products of diges- 

 tion on the water bath yielding a paste 

 of the consistency and color of 

 Liebig's meat extract. 



(3) Add 100.0 g. (10.0%) of 2 to 100.0 cc. 

 tap water. 



(4) Adjust the reaction to +1.0. 

 Sterilization: Method not given. 



Use: General culture medium. The author 

 suggested that the term "trypsinoid" be 

 employed for the paste. Brewer's yeast 

 and fresh yeast were treated in exactly 

 the same manner but the casein product 

 gave the best results. 



Variants : 



(a) The paste from (2) may be further 

 dried in a desiccator over H2SO4, 

 yielding a brittle resinous mass which 

 may be powdered. 



(b) The author dissolved (2) in physio- 

 logical salt solution instead of tap 

 water. 



Reference: Norris (1920 p. 706). 



1133. Cannon's Trypsinized Casein Solution 

 (Norton and Sawyer) 



Constituents : 



1. Distilled water 1000.0 cc. 



2. Casein (c.p.) 20.0 g. 



3. Asparagin 5.0 g. 



4. Ammonium lactate 5.0 g. 



5. K2HPO4 2.0 g. 



6. MgS04 0.2 g. 



Preparation : 



(1) Add 20.0 g. casein to 250.0 cc. distilled 

 water and make alkaline to phenol- 

 phthalein with Na2C03. 



(2) Add 0.5 g. trypsin and allow to digest 

 for 6 hours. 



