790 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



Preparation : 



(1) Thoroly mix the white and yolk of an 

 egg before breaking the shell by 

 shaking the egg vigorously. 



(2) Remove the contents of the egg under 

 aseptic conditions. 



(3) Distribute into sterile test tubes. 



(4) Coagulate by heat. 

 Sterilization: Method of sterilization of 



test tubes not given. 

 Use: Cultivation of plant parasites. 

 Reference: Smith (1905 p. 49). 



2435. Dorset's Egg Medium (Heinemann) 



Constituents: 



1. Egg. 

 Preparation : 



(1) Break eggs in a flask. 



(2) Break the yolk with a platinum wire. 



(3) Shake the flasks gently. Do not 

 cause to foam. 



(4) Tube in 10.0 cc. quantities. 



(5) Heat in a Koch inspissator for 2 suc- 

 cessive days for 4 or 5 hours at 70°C. 



Sterilization: Not specified. 

 Use: General culture medium. 

 Variants: The following authors prepared 

 similar media as indicated. 



(a) Abel. 



(1) Carefully wash and brush the shell 

 of an egg. 



(2) Wash in a 5.0% sublimate solution 

 and in sterile water. 



(3) Dry with sterile wool. 



(4) INIake an opening in either pole of 

 the egg and blow the contents into 

 a sterile test tube, flask or plates. 



(5) Coagulate in the same manner as 

 blood serum. 



(b) Waksman studied the metabolism of 

 actinomycetes on the following 

 medium : 



(1) Sterilize egg on surface. 



(2) Transfer contents into sterile con- 

 tainers. 



(3) Mix with sterile spatula. 



(4) Tube, slant, coagulate. 



(5) Sterilize in Arnold at 75 to 90° for 

 3 consecutive days. 



(c) Scales studied the variation in mor- 

 phology of B. colt in a medium pre- 

 pared as follows : 



(1) Strain fresh eggs 4 times thru four 

 thicknesses of cheese cloth. 



(2) Pour into a small suction flask and 

 place under a vacuum for 5 minutes 

 with occasional shaking. 



(3) Distribute in test tubes (0.75 cc. 

 in tube 4 inches by ^ inch) with a 

 pipette. 



(4) Coagulate in slanting position in 

 boiling water or in an inspissator. 



(5) After coagulated, cover egg with 

 cold distilled sterile water. 



(6) Plug and autoclave at 16 pounds for 

 30 minutes. 



(7) Pour off water just before using. 

 References : Heinemann (1905 p. 130), Abel 



(1912 p. 27), Tanner (1919 p. 58), 

 Waksman (1919 p. 307), Scales (1921 p. 

 595), Pitfield(1922p. 120). 



2436. Modified Dorset's Egg Medium 

 (Brown and Smith) 



Constituents : 



1. Distilled water 25.0 cc. 



2. Whole egg 100.0 cc. 



Preparation : 



(1) Sterilize the shell of eggs. 



(2) Mix, in sterile container, the white 

 and yolk thoroly after removing from 

 the shell. 



(3) Add sterilized distilled water equal 

 in amount to 24.0% by volume. 



(4) Tube, avoiding air bubbles. 



(5) Slant and heat to 85°C. in the or- 

 dinary blood serum coagulator on 3 

 successive days. 



Sterilization: Not specified. 



Use: Isolation of tubercle bacilli from 

 sputum by the use of antiformin. 



Variants: The following investigators pre- 

 pared the medium as follows: 

 (a) Park and Krumwiede. 



(1) Wash eggs thoroly in water and 

 then in 5.0% phenol solution and 

 allow to partially dry. 



(2) Dry the ends of the eggs gently in 

 the flame and pierce with a burned 

 sharp forcep. The hole at one 

 end should be about f of an inch 

 in diameter and the membrane 

 broken. The other end which is 

 to be blown into should be smaller 

 and the membrane left unbroken. 



(3) Blow the contents of the egg into 

 a sterile Erlenmeyer flask. 



