CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



381 



(2) Stir briskly for a few seconds. 



(3) Allow to coagulate. 



(4) When the curd has formed cut with 

 a knife, and leave it for an hour so 

 that the whey may separate. 



(5) Filter thru muslin. 



(6) Add the white of an egg whipped up 

 with 100.0 g. of water. 



(7) Heat in a steam sterilizer for an 

 hour. 



(8) Filter into test tubes. 



(9) Sterilize on 3 successive days for 20 

 minutes each day. 



(c) Klimmer gave the following method 

 of preparation: 



(1) Add a little rennet to milk obtained 

 under the cleanest possible condi- 

 tions and heat to 40°C. until the 

 casein is coagulated. 



(2) Separate the casein from the whey 

 by straining thru a straining cloth. 



(3) Filter the whey thru filter paper 

 and then thru an asbestos filter. 



(4) Distribute in sterile flasks. 



(5) Sterilize by the addition of 1.5% 

 chloroform. 



References: Stutzer and Hartleb (1897 p. 

 403), Percival (1920 p. 58), Klimmer (1923 

 p. 203). 



1306. Emile-Weil's Litmus "Whey Solution 



Constituents : 



1. Whey 1000.0 cc. 



2. Litmus 



3. CaCh 2.0 g. 



Preparation : 



(1) Skim milk. 



(2) Heat to 40 °C. 



(3) Add an excess of rennet tablets (6 

 tablets per liter). 



(4) Allow to coagulate for 30 minutes. 



(5) Cut the curd into large pieces. 



(6) Filter thru a thin cloth. 



(7) Make the filtrate alkaline to phenol- 

 phthalein by the addition of soda. 



(8) Add 2.0 g. CaCh per liter. 



(9) Heat at 110° for 15 minutes. 



(10) Filter thru paper until the filtrate is 

 clear. 



(11) The reaction should be a deep violet 

 to litmus. 



(12) Add 2.0% litmus solution to obtain 

 the desired shade. 



(13) Filter thru a candle. 



(14) Distribute in test tubes. 



(15) Incubate two days in the incubator 

 and 8 days at room temperature to 

 test sterility. 



Sterilization: Sterilization is effected in 



step (13) above. 

 Use: Cultivation of Bacillus leprae. May 



be used as a general culture medium. 

 Variants : The author used the medium with 



a neutral, alkaline or acid reaction. 

 References: Emile-Weil (1917 p. 380), Bes- 



son(1920p.59). 



1307, Durham's Litmus Whey Solution 



Constituents: 



1. Whey 



2. Litmus 

 Preparation: 



(1) Fresh milk free from antiseptic 

 adulteration is slightly warmed and 

 clotted by means of rennet. 



(2) Drain off the whey and hang the clot 

 to drain in a piece of muslin. 



(3) Neutralize the turbid or yellow whey 

 with 4.0% citric acid solution, using 

 litmus as an indicator. 



(4) Heat upon the water bath for 30 

 minutes to coagulate the proteins. 



(5) Filter and add litmus to obtain a 

 suitable color. 



(6) Distribute in 10.0 cc. quantities if 

 desired. 



Sterilization: Sterilize at 100°C. If not 

 perfectly clear filter thru a Berkefeld 

 filter after allowing to settle a few days. 



Use: Cultivation of the colon-typhoid 

 group. 



Variants : 



(a) Heinemann prepared the medium as 

 follows: 



(1) Precipitate casein from milk with 

 rennet extract. 



(2) Neutralize the whey with 4.0% 

 citric acid solution. 



(3) Heat on the water bath for 30 

 minutes. 



(4) Filter. 



(5) Add litmus solution until a decided 

 blue color is obtained. 



(6) Sterilization not specified. 



(b) Harvey prepared a similar medium 

 as follows: 



(1) Add rennet to fresh milk. 



(2) Keepat60°C. 



