CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



383 



Preparation : 



(1) To 1 liter of milk add 10.0 cc. of 15° 

 Baume (equivalent to 25.0 g. crystal- 

 line CaCh per 100.0 cc. water) 

 CaCh solution. 



(2) Heat in the autoclave at 115° for 4 or 

 5 minutes, more or less, depending 

 on the coagulation. 



(3) Cool, without shaking. 



(4) Filter thru linen. 



(5) Add a dilute soda solution until 

 litmus is colored. 



(6) Boil for one minute and allow to cool. 



(7) Decant and filter. The filtrate is 

 clear. 



(8) Mix with 2 or 3 volumes of distilled 

 water. 



(9) Add a tincture of litmus solution 

 (amount not given) to give the de- 

 sired color. 



(10) Distribute in tubes or flasks. 

 Sterilization: Sterilize at 110 to 112°C. 

 Use: Cultivation of colon typhoid group. 

 Variants: Besson and Harvey did not 



dilute the whey with 2 or 3 volumes of 



water as in step (8) above. 

 Reference: Jouan (1916 p. 520), Besson 



(1920 p. 60), Harvey (1921-22 p. 96). 



1311. Petruchsky's Litmus Whey Solution 

 (Grimbert and Legros) 



Constituents: 



1. Whey. 



2. Litmus. 

 Preparation: 



(1) Heat cold milk to a gentle heat (tem- 

 perature not given). 



(2) Add sufficient HCl to precipitate the 

 casein. 



(3) Filter. 



(4) Add soda solution until the reaction 

 is but only slightly acid. 



(5) Heat in a Koch steamer for several 

 hours. 



(6) Filter. 



(7) Neutralize exactly to litmus. 



(8) Color with sensitive litmus. 

 Sterilization: Not specified. 



Use: Differentiation of colon-typhoid 

 group. Author reported that colon bacilli 

 turned medium strongly red. Typhoid 

 bacilli produced only slight acidity. B. 

 faecalis alcaligenes gave an alkaline 

 reaction. 



Variants : 



(a) Migula prepared a similar medium as 

 follows: 



(1) Mix equal volumes of fresh milk 

 and water. 



(2) Add HCl until the casein is 

 precipitated. 



(3) Filter. 



(4) Carefully neutralize the whey. 



(5) Boil for 1 to 2 hours. 



(6) Filter and allow to stand until 

 the whey is completely clear. 



(7) The whey may be clarified by the 

 addition of egg white. 



(8) Tube, or distribute in flasks and 

 store until ready for use. Steri- 

 lize in steam. 



(9) When ready for use add sufficient 

 litmus tincture (About 5.0 cc. per 

 100.0 cc. whey) to give a violet 

 color. 



(10) Steam again. 



(b) Bezanfon gave the following method 

 of preparation for the medium: 



(1) Add drop by drop from a burette 

 10.0% HCl to 100.0 cc. of boiling 

 milk until the casein is completely 

 coagulated. Stir constantly. 



(2) Add a sufficient quantity of HCl, 

 (calculated from (1)), to cause 

 complete coagulation of casein in 

 1000.0 cc. of boiling milk. Add 

 the HCl drop by drop, stirring 

 constantly. 



(3) Allow to stand for several hours. 



(4) Decant the liquid whey. 



(5) Filter several times until clear. 



(6) Neutralize. 



(7) Add sufficient litmus solution to 

 give a violet tint. 



(8) Tube. 



(9) Sterilize by heating at 100°C. by 

 the intermittent method. 



(c) Besson prepared the medium as 

 follows: 



(1) Dilute 1.0 cc. of HCl in 20.0 cc. of 

 water. 



(2) Add (1) to 1 liter of fresh milk. 



(3) Heat at 110° for 15 minutes. 



(4) Allow to cool. 



(5) Filter thru Chardin paper. 



(6) Make slightly alkaline and heat. 



(7) Add litmus until a light violet 

 color is obtained. 



