CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



459 



(6) Filter. 



(7) To hot (6) gradually add a suspension 

 of 30.0 g. washed starch made per- 

 fectly homogeneous in a mortar. 

 Stir constantly. 



(8) Bring near the boiling point and 

 weigh. Total weight should be 

 1000.0 g. 



(9) Tube. 



Sterilization: Sterilize in autoclave at 120° 

 for 5 minutes 



Use: Substitute for potato as a culture 

 medium. Author reported that the me- 

 dium was superior to potato for the com- 

 position is always the same, reaction can 

 be adjusted and pigment formation can 

 be better studied. 



References: Heinemann (1907 p. 283), (1922 

 p. 29), Besson (1920 p. 57). 



1594. MacConkey's Basal Bile Salt Peptone 

 Agar 



Constituents: 



1. Water 1000.0 cc. 



2. Sodium glycocholate 



(0.5%) 5.0 g. 



3. Peptone (1.5%) 15.0 g. 



. Agar (1.5%) 15.0 g. 



Preparation: 



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



(2) Filter. 



(3) Dissolve one of the added nutrients 

 in (2). 



Sterilization: Method not specified. 



Use: Differentiation Bacillus coli commune 



and Bacillus typhi abdominalis. 

 Added nutrients: The author added 0.3 to 



0.5% lactose or glucose. 

 Variants : 



(a) Frost prepared a similar medium as 

 follows: 



(1) Dissolve 20.0 g. of agar in a liter of 

 boiling water. 



(2) Dissolve 20.0 g. of peptone in a 

 liter of boiling water. 



(3) Mix (1) and (2). 



(4) Make alkaline by the addition of 

 4.0 cc. of a normal sodium hydrate 

 solution, after neutralizing the 

 litmus. 



(5) While hot add 5.0 g. of sodium 

 taurocholate, 10.0 g. of lactose and 

 10.0 cc. of a 5.0% watery solution 

 of neutral red. 



(6) When the solution is complete, 

 filter thru cotton. 



(7) Tube. 



(8) Sterilize in the steam sterilizer 

 once for 25 or 30 minutes. 



(b) MacConkey specified the use of 2.0% 

 Witte's peptone, 0.5% commercial 

 sodium taurocholate, added 0.5% of a 

 1.0% solution of neutral red, 1.0% 

 glucose or any other carbohydrate 

 and 0.034% CaCl., 0.5% KNO3 or 

 0.5% KI might be added. The 

 medium was clarified with white of 

 egg before the addition of neutral red 

 and carbohydate, and sterilized in the 

 steamer for 10 minutes on each of two 

 successive days. The salts, CaCU, 

 KXO3 and KI, in the concentrations 

 given, stimulated the growth of 

 lactose fermenters. 



(c) MacConkey used litmus in the above 

 variant instead of neutral red. 



(d) MacConkey used 1.5 to 2.0% agar in 

 the preparation of variant (b) and 

 added 1.0% serum or 1.0% alkali- 

 haematin solution, (CaCl2, KNO3 or 

 KI were not used in this medium). 



(e) Abel used 0.4% of a 1.0% neutral red 

 solution in MacConkey's medium, 

 variant (b) and specified the use of 

 lactose as a carbohydrate. 



(f) Ball prepared a medium containing 

 5.0 g. of sodium taurocholate, 15.0 g. 

 peptone, 35.0 g. lactose and 15.0 g. of 

 agar per liter. 



(g) Fercival prepared a medium as 

 follows: 



(1) Dissolve 5.0 g. sodium tauro- 

 cholate, 20.0 g. peptone, and 15.0 

 g. of agar in 1000.0 cc. of water by 

 heating in a water bath for one 

 hour. 



(2) Cool to 50°C. 



(3) Add the white of an egg and heat in 

 the water bath for 90 minutes. 



(4) Filter. 



(5) Add 1.0 g. lactose, 1.0 cc. of a 

 0.5% solution of neutral red and 

 1.0 cc. of a 0.1% solution of crys- 

 tal violet, per 100.0 cc. of the 

 filtrate. 



(6) Tube in sterile tubes in 10.0 cc. 

 quantities. 



