742 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



2298. Heinemann's Peptone Extract Gelatin 

 Constituents: 



1. Water (tap) 1000.0 cc. 



2. Meat extract 2.5 g. 



3. Peptone 10.0 g. 



4. Gelatin 100.0 to 120.0 g. 



Preparation : 



(1) Dissolve 2.5 g. meat extract in 

 1150.0 cc. of tap water. (Added 

 150.0 cc. of water to be lost during 

 preparation.) 



(2) Heat and when near boiling add 10.0 g. 

 peptone to (1). 



(3) When boiling add 10.0 to 12.0% of the 

 best Gold Label gelatin to (2). Add 

 2 or 3 sheets of gelatin at a time, 

 stirring constantly. 



(4) When solution is complete adjust the 

 reaction to alkaline to litmus or 

 neutral to phenolphthalein and then 

 add 0.5% normal HCl. 



(5) Cool to 60°C. and stir in the white of 

 one egg dissolved in 30.0 cc. water. 



(6) Heat over the flame on a piece of 

 asbestos without stirring. Heat until 

 the egg albumin is completely coagu- 

 lated and forms a dry film on top. 



(7) Add water to make up any loss in 

 weight over 50.0 g. 



(8) Filter thru paper or absorbent cotton 

 previously moistened with hot water. 



(9) Tube in 10.0 cc. quantities. 

 Sterilization : Sterilize in the autoclave for 



5 minutes at 120 °C. or steam for 3 suc- 

 cessive days for 20 minutes each day. 

 Use: General culture medium. 

 Variants : 



(a) Wherry used the following medium to 

 determine effect of reaction and dry- 

 ness on liquefaction of gelatin by 

 Cholera spirillum. 



(1) Dissolve 200.0 g. Gold Label gela- 

 tin, 10.0 g. Witte's peptone and 

 30.0 g. Liebig's beef extract in 

 1000.0 cc. water. 



(2) Divide (1) into two 500.0 cc. lots. 



(3) To one lot add NaOH so that after 

 sterilization the final reaction is 

 -1-0.8. 



(4) To the other portion add NaOH so 

 that the final reaction after steri- 

 lization is +1.0. 



(5) Method of sterilization not given. 



(b) Bahr reported that Gartner's bacillus 

 did not liquefy a medium prepared 

 as follows : 



(1) Dissolve 200.0 g. gelatin, 10.0 g. 

 peptone, 20.0 g. meat extract 

 (Cibil's) in 1000.0 cc. of water. 



(2) Adjust so that 10.0 cc. of the me- 

 dium will titrate 0.3 with N/10 

 NaOH using phenolphthalein as an 

 indicator. 



(3) Sterilization not specified. 



(c) Commiteee A. P. H. A. (1917) (1920) 

 gave the following method of prepa- 

 ration : 



(1) Add 3.0 g. of beef extract and 5.0 g. 

 peptone to 1000.0 cc. of distilled 

 water and add 100.0 g. gelatin, 

 dried for 30 minutes at 105 °C. before 

 weighing. 



(2) Heat slowly on a steam bath to 

 65°C. until all the gelatin is dis- 

 solved. (May be soaked for 30 

 minutes before heating.) 



(3) Make up lost weight, titrate and 

 if the reaction is not already be- 

 tween +0.5 and +1.0, adjust to +1. 



(4) Filter thru cloth and cotton until 

 clear. 



(5) Distribute in tubes in 10.0 cc. 

 quantities or in larger amounts as 

 desired. 



(6) Sterilize in the autoclave at 15 

 pounds (120°C.) for 15 minutes 

 after the pressure reaches 15 

 pounds. 



(d) Committee S. A. B. (1918) recom- 

 mended the same medium as Com- 

 mittee A. P. H. A. (1917) but clarified 

 with egg and adjusted to pH between 

 6.6 and 7.4. 



(e) Treece dissolved 12% gelatin, 2.0% 

 peptone and 0.5% meat extract in 

 water. The medium was used to 

 determine fecal and non-fecal strains 

 of the colon-aerogenes group. The 

 author reported that this medium 

 correlated the fermentation of ado- 

 nitol. Positive results were indi- 

 cated by a line of 4 to 8 bubbles 

 extending down the line of isolation. 



(f) Committee A. P. H. A. (1923) ad- 

 justed the medium to a faint pink 

 with phenol red or to the required 



