CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



315 



water.) Add HCI to stop the di- 

 gestion. 



Sterilization: Method not given. 



Use: Indol production. Use this digest in 

 1.0 or 2.0% solution for indol reaction. 

 Author reported that the addition of 

 0.1% of this digest gave equally as good 

 growth when added to nutrient medium 

 as did 1.0% Witte's peptone. 



Reference: Bramigk (1921 p. 431). 



1112. Jensen's Milk Digest Solution 



Constituents: 



1. Milk 1000.0 cc. 



Preparation : 



(1) To sterilized milk add 10.0 cc. of pure 

 concentrated HCI per liter and 2.0 g. 

 of a pure pepsin preparation. 



(2) Incubate at 35-37° for 36 to 48 hours 

 shaking often at first until the casein 

 has precipitated and to dissolve the 

 pepsin, and then only occasionally. 



(3) Approximately neutralize the acid 

 (acid hydrolyzes the lactose when 

 heated) and heat in the autoclave at 

 115 to 120° for 10 minutes. 



(4) Filter thru paper. 



(5) Adjust the reaction (neutral to lit- 

 mus). 



(6) May be clarified with egg white if 

 desired. 



Sterilization : Sterilize in the usual manner. 

 Use: Cultivation of lactic acid bacteria. 

 Reference: Jensen (1898 p. 199). 



1113. Stickel and Meyer's Tr)rpsinized 

 Blood Clot Solution 



Constituents: 



1. Water, tap 1000.0 cc. 



2. Blood clots 500.0 g. 



3. K0HPO4 2.0 g 



Preparation : 



(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 

 500.0 g. with 1 liter tap water. 



(4) Place the mixture in an enameled 

 pot, bring slowly to a boil, and boil 

 slowly for 5 minutes, stirring con- 

 stantly. 



(5) Strain fluid thru cheese cloth and 

 pass the residue thru a fruit press, 

 cool to 37°C. 



(6) Make the thick brownish fluid 

 slightly alkaline to litmus. 



(7) Add 1.0% pancreatic extract and 

 incubate at 37° for 5, 24, 48 hours. 



(8) When the process is sufficiently ad- 

 vanced, render slightly acid with 

 glacial acetic acid and boil slowly 

 for 15 minutes. 



(9) Either filter or decant the clear fluid 

 which results on placing the digest 

 over night in a cool place. 



(10) Adjust the reaction as desired. 



(11) Dissolve 3 in (10). 



(12) Heat for 15-30 minutes in the 

 steamer at 100 °C. 



(13) Filter again if necessary. 



(14) Clear (13) by adding 5-10.0% of the 

 decanted beef serum. Steam 45- 

 60 minutes. 



(15) Remove (14) from steamer and allow 

 clot to form as a compact mass. 

 Decant, or better, centrifuge the 

 medium to remove the clot. * . 



Sterilization: Sterilize at 100° for 30 min- 

 utes on each of 2 successive days. 



Use: Author reported that this medium 

 was excellent for primary isolation of 

 highly parasitic organisms. 



Variants: Knorr prepared a similar me- 

 dium as follows: 



(1) Mix 1 kilo of blood clots with 

 1500.0 cc. water, and boil for 1 hour 

 on an open flame. Stir often. 



(2) Press the fluid thru a filtering cloth 

 and run the blood clot thru a meat 

 grinding machine. 



(3) Add the ground blood clot to the 

 fluid. Stir. 



(4) Add 1.0 to 2.0 g. pancreatin and 

 chloroform and digest for 6 to 7 

 days at room temperature. Mix the 

 chocolate brown liquid often. 



(5) Acidify to stop the digestion. 



(6) Filter thru paper. 



(7) Add enough water to the residue to 

 make a 4000.0 cc. stock solution. 



(8) Add 100.0 g. of rock salt (cattle salt) 

 and 15.0 g. potassium phosphate. 



(9) Filter. This is the stock solution. 

 It gives a tryptophane reaction. 



