CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



549 



green, while colon colonies were brilliant 

 yellow. The addition of brilliant green 

 did not interfere with the color produc- 

 tion of the non-lactose fermenters. 

 Variants: The author prepared a similar 

 medium as follows: 



(1) Prepare a 3.0% beef extract agar and 

 adjust to pH = 7.6 to 7.8. 



(2) Clear (1) with white of an egg. 



(3) Sterilization not mentioned. 



(4) Add 1.0% lactose from a sterile 20.0% 

 solution. 



(5) Add for every 100.0 cc. of the medium, 

 10.0 cc. of an 0.04% aqueous solution 

 of phenol red. This solution may be 

 sterilized by autoclaving. 



(6) Pour into sterile Petri dishes, about 

 20.0 cc. of agar to the plate. 



The author reported that the medium was 

 originally salmon pink or old rose. Lac- 

 tose fermenters produced vivid greenish 

 yellow colonies with a surrounding zone 

 of green. The typhoid bacillus, the 

 paratyphoid bacillus (A and B) and the 

 dysentery bacilli (Shiga, Flexner and 

 Hiss Y) all produced pink colonies. In 

 very thickly seeded plates the colon 

 colonies assumed a bright green or yellow 

 green color and are opaque, whereas the 

 typhoid colonies were more translucent 

 and possessed a bluish green color. 

 Typhoid colonies had a corrugated, 

 woolly appearance. The addition of 

 brilliant green did not interfere with the 

 color production of the non-lactose 

 fermenters. 

 Reference: Chesney (1922 pp. 183, 184). 



1762. Salomonsen's Sucrose Extract Agar 

 (Besson) 



Constituents: 



1. Water 1000.0 cc. 



2. Meat extract (Liebig's) .... 5 g. 



3. Peptone 30.0 g. 



4. NaCl 5.0 g. 



5. Agar 20.0 g. 



6. Sucrose 5.0 g. 



Preparation: 



(1) Dissolve 2, 3, 4 in 1. 



(2) Soak 20.0 g. of chopped thread agar 

 in cold water for several hours. 

 Squeeze water thru a cloth. 



(3) Heat (2) in (1) at 100°C. until the 

 agar is dissolved. 



(4) Readjust the reaction if necessary. 



(5) Allow to cool to 55 or 60°C. 



(6) Beat the white of an egg in 100.0 cc. 

 of water and add to (5) . 



(7) Mix well. 



(8) Autoclave at 120°C. for one hour. 



(9) Add 5.0 g. of sucrose to (8). 

 (10) Tube. 



Sterilization: Sterilize at 115°C. for 20 



minutes. 

 Use: General culture medium. 

 Reference: Besson (1920 p. 43). 



1763. Hesse's Starch Extract Agar (Stokes 

 and Hachtel) 



Constituents: 



1. Distilled water 1000.0 cc. 



2. Agar 5.5 g. 



3. Beef extract (Liebig's) 5.0 g. 



4. Peptone (Witte's) 10.0 g. 



5. Starch 10.0 g. 



6. NaCl 8.5 g. 



7. Azolitmin solution (Kahl- 

 baum's) 



Preparation : 



(1) Dry agar at 105°C. for 30 minutes. 



(2) Dissolve 5.5 g. of (1) in 500.0 cc. 

 distilled water. 



(3) Add 5.0 g. beef extract to 500.0 cc. 

 of distilled water and dissolve by 

 heat. 



(4) Filter (3) into a sterile flask and 

 inoculate with the colon bacillus 

 and incubate at 37°C. for 24 hours. 



(5) Filter the sugar free bouillon and 

 dissolve 10.0 g. Witte's peptone, 

 10.0 g. starch and 8.5 g. NaCl in it. 



(6) Make up the loss due to evaporation 

 by the addition of distilled water. 



(7) Mix (6) and (2) and boil for 30 

 minutes, making up the loss in 

 weight by the addition of distilled 

 water. 



(8) Filter. 



(9) Adjust the reaction to neutral. 



(10) Color with Kahlbaum's azolitmin 

 solution. 



(11) Distribute in 10.0 cc. lots. 



(12) Store in the ice box until ready for 

 use. 



Sterilization: Autoclave at 16 pounds pres- 

 sure for 20 minutes. 

 Use: Differentiation of typhoid bacillus. 



