314 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



(10) Adjust to desired reaction. 



(11) Add 0.2-0.4% K2HPO4 and 2.0% 

 of purified talcum. 



(12) Filter thru paper. 



(13) Distribute for use. 



(14) Sterilize at 100°C. for 30 minutes 

 on 2 successive days or at 10 

 pounds pressure for 15 minutes. 



(b) Park, Williams and Krumwiede omit- 

 ted the K2HPO4. 

 References : Stickel and Meyer (1918 pp. 78, 

 79), Harvey (1921-22 p. 99), Park, Wil- 

 liams and Krumwiede (1924 p. 119). 



1009. Frieber's Gelatin Digest Solution 



Constituents: 



1. Water 2000.0 cc. 



2. Gelatin 20.0 g. 



3. NaCl 5.0 g. 



4. KH2PO4 2.0 g. 



5. MgS04 0.2 g. 



6. Tryptophane 0.3 g. 



Preparation : 



(1) Add 20.0 g. of gelatin, 10.0 cc. HCI 

 and 2.0 g. Witte's peptone to 2 liters 

 of water and allow to digest for 

 several days. 



(2) Neutralize to litmus by adding 

 NaOH. 



(3) Dilute (2) with an equal volume of 

 water. 



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



(5) Add 7.0 cc. of normal soda solution. 

 Sterilization: Not specified. 



Use: Indol production. 

 Reference: Frieber (1921-22 p. 263). 



1110. Frieber's Fibrin Digest Solution 



Constituents : 



1. Water. 



2. Fibrin. 



3. NaCl 0.5% 



Preparation : 



(1) Wash fibrin in running water until 

 it is white. Press out the water. 

 The fibrin containing about 25% 

 dry material is placed in a flask so 

 that the flask is about ^ full. 



(2) Add to each liter flask about 3 to 

 5 grams pepsin powder and fill the 

 flask with water. 



(3) For each liter of material add 10.0 cc. 

 of concentrated (1.19) HCI. 



(4) Shake thoroly. 



(5) Allow the flask to stand at room 

 temperature or in the incubator. 

 Shake thoroly several times a day. 



(6) Add 5.0% HCI from time to time. 

 Use Congo red as an indicator (blue 

 color). 



(7) About 10 to 14 days are required for 

 complete digestion of the fibrin. 

 The reaction may be allowed to reach 

 acid to litmus at this time. 



(8) Allow the digest to stand undis- 

 turbed for 2 or 3 days. 



(9) In order to obtain a fat-free digest, 

 remove the bottom dark brown 

 digest by means of a rubber tubing. 

 The fat floats on the top surface. 



(10) In order to obtain about a 1.0% 

 peptone solution dilute the stock 

 solution about 3 with water and add 

 5.0% NaOH solution to neutralize 

 to litmus. 



(11) A heavy flaky precipitate is formed. 

 Do not add an excess of NaOH or 

 the precipitate will dissolve. 



(12) Boil and filter or allow the pre- 

 cipitate to settle. This gives a light 

 yellowish 1.0% peptone solution. 

 It is necessary to add 0.5% NaCl. 



(13) Distribute in flasks. 

 Sterilization: Method not given. 



Use: Substitute for commercial peptone. 

 Reference: Frieber (1921 p. 425). 



1111. Bramigk's Peptic Tryptic Digest 

 Solution 



Constituents: 



1. Water 4000.0 cc. 



2. Blood clot 1000.0 g. 



3. Stomach (hog) 2 



Preparation : 



(1) Prepare Bramigk's Blood Clot Digest 

 solution, see medium 1004. 



(2) Add Ba(0H)2 to 1000.0 cc. of (1) until 

 the reaction is only slightly acid. 



(3) Boil to clarify. 



(4) Add without filtration 5.0 cc. water 

 free soda (strength solution not 

 given), 5.0 cc. toluol, 5.0 cc. chloro- 

 form, and 2.0 g. pancreaten (Rhe- 

 nania). 



(5) Mix well and incubate at 37° for 120 

 hours, shaking occasionally. (Test 

 for tryptophane using bromine 



