654 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



2037. Stickel and Meyer's Peptic Digest 



Agar 

 Constituents: 



1. Water, tap 4000.0 cc. 



2. Pig's stomach, minced 400.0 g. 



3. Liver, minced (beef pla- 

 centa or blood clots) 400.0 g. 



4. HCl (Baker Chemical Co.). 40.0 g. 



5. K2HPO4 8.0 g. 



6. Agar 80.0 g. 



Preparation : 



(1) Wash clean and mince fine five or 

 more large pigs' stomachs. Mix an 

 equal amount of clean pig or beef 

 liver, cheap fat-free beef, placenta 

 or blood clots. 



(2) Mix 2, one of 3, and 4 in 1 at 50°C. 

 and keep at 50°C. for 18-24 hours. 



(3) Make a Biuret and trj-ptophane 

 test. When both are + the digest 

 is yellowish green and contains very 

 little undigested debris. 



(4) Transfer to large bottles and steam 

 for 10 minutes at 100°C. to stop 

 digestion. 



(5) Strain thru cotton or preferably 

 store over night in the ice chest and 

 decant after 24 hours. 



(6) Warm (5) to 70°C. and neutralize 

 with 2N Na2C03 to litmus. 



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



(8) Autoclave at 10 pounds pressure for 

 45 minutes or heat in double boiler 

 to 100°C. until the agar is dissolved. 



(9) Restore the volume lost by evapo- 

 ration. 



(10) Adjust to slightly alkaline to litmus 

 or pH = 7.3 bv using 2N KOH or 

 NaOH. 



(11) Cool to 60°C. and add white of egg 

 with crushed shells or for sake of 

 economy, ordinary beef or sheep 

 serum in the quantity of 25-50 cc. 

 per liter. 



(12) Autoclave for one hour at 115°C. 



(13) Filter thru cotton and distribute in 

 200-500 cc. quantities. 



Sterilization: Sterilize at 100° for 30 min- 

 utes on 2 successive days or at 10 pounds 

 pressure for 15 minutes. 



Use: General inexpensive culture medium. 



Variants : 



(a) The authors prepared a sugar free 

 medium as follows: 



Carry out step (1) thru (6) as 

 given above. 



(7) Sterilize at 10 pounds pressure for 

 15 minutes in the autoclave or for 

 30 minutes at 100°C. on 2 suc- 

 cessive days. 



(8) Inoculate (7) with 1.0% of a 

 24 hour old broth culture of B. 

 saccharolyte or B. coli and incu- 

 bate for 12-18 hours at 37°C. 



(9) Steam 20 minutes. 



(10) Adjust to desired reaction. 



(11) Add 5 and 6 to (10). 



(12) Autoclave at 10 pounds pressure 

 for 45 minutes or heat in double 

 boiler to 100°C. until the agar 

 is dissolved. 



(13) Restore the volume lost by evap- 

 oration. 



(14) Adjust to slightly alkaline to lit- 

 mus or pH = 7.3 by using 2N 

 KOH or NaOH. 



(15) Cool to 60°C. and add white of egg 

 with crushed shells or for sake of 

 economy, ordinary beef or sheep 

 serum in the quantity of 25-50 cc. 

 per liter. 



(16) Autoclave for one hour at 115°C. 



(17) Filter thru cotton and distribute in 

 200.0 to 500.0 cc. quantities. 



(18) Sterilize at 100° for 30 minutes on 

 2 successive days or at 10 pounds 

 pressure' for 15 minutes. 



(b) Stickel and Meyer prepared a me- 

 dium as follows: 



(1) Obtain 10 liters fresh beef blood 

 from the abattoir. 



(2) Decant and store the serum (which 

 has separated on standing) in a 

 refrigerator. 



(3) Weigh the blood clots and mix 

 100.0 g. with 1 liter tap water. 



(4) Place mixture in an enameled pot, 

 bring slowly to a boil and boil 

 slowly for 5 minutes, stirring con- 

 stantly. 



(5) Wash and mince pig's stomach. 



(6) Cool (4) to 50 °C. and add 100.0 g. 

 minced pig's stomach for each 

 liter of (4). 



(7) Transfer to glass or porcelain 

 receptacle and finally add 1.0% 

 HCl. 



(8) Digest at 50°C. for 18-24 hours. 



