530 



CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



from the edge. The medium must 

 be kept in a dark place because the 

 color is restored by the action of 

 daylight. 

 (e) Harvey. 



(1) Add 3.7 cc. of a 10% anhydrous 

 sodium carbonate solution to 

 1000.0 cc. of infusion agar (see 

 variant (v) medium 1661). 



(2) Dissolve 2.0 g. lactose in 25.0 cc. 

 of distilled water. 



(3) Dissolve 0.5 g. anhydrous NaoSOs, 

 and 1.0 cc. of a saturated alcoholic 

 basic fuchsin solution in 10.0 cc. 

 distilled water. 



(4) Mix (2) and (3). 



(5) Add (4) to (1). 



(6) Pour in plates. 



(7) Dry the surface of the medium 

 for 15 minutes in the incubator. 



(f) Harvey. 



(1) Add 10.0 cc. of a 10.0% crystalline 

 sodium bicarbonate solution to 

 1000.0 cc. of infusion agar (see 

 variant (v) medium 1661) neutral 

 to litmus. 



(2) Prepare an alcoholic fuchsin solu- 

 tion by adding 1.0 g. basic fuchsin 

 to 20.0 cc. absolute alcohol, allow- 

 ing it to stand 24 hours, and centri- 

 fuge. (A filtered saturated alco- 

 holic fuchsin in the same or half 

 the quantity may be used.) 



(3) Add 10.0 g. c. p. lactose and 5.0 cc. 

 of (2) to (1). 



(4) Add 10.0%, freshly prepared crys- 

 talline sodium sulphite 25. 



(5) Distribute into test tubes or flasks. 



(6) Sterilize at 115°C. 



(7) Keep in the dark until used, 

 (g) Harvey. 



(1) Add 10.0 g. lactose to infusion 

 agar (see variant (v) medium 

 1661) with a reaction of 0.5% 

 alkaline to phenolphthalein. 



(2) Filter (1). 



(3) Add 5.0 cc. of alcoholic fuchsin 

 solution prepared as indicated in 

 step (2) variant (d) above. 



(4) Mix. 



(5) Add 10.0% freshly prepared so- 

 dium sulphite 25. 



(6) Sterilize. 



References: Endo (1905 p. 109), Reitz (1906 



p. 722), Abel (1912 p. 131), Stroszner 

 (1917-18 p. 224), Zipfel (1917-18 p. 477), 

 Levine (1921 p. 114), Harvey (1921-22 

 pp. 92, 93). 



1730. Wurtz's Litmus Lactose Agar 



Constituents: 



1. Infusion Agar 1000.0 cc. 



2. Lactose (2.0%) 20.0 g. 



3. Litmus 

 Preparation : 



(1) Add 2.0% lactose to infusion agar 

 with a slightly alkaline (0.5% re- 

 action). 



(2) Tint sterile (1) by the addition of a 

 sufficient quantity of sterile litmus 

 solution. 



Sterilization: Sterilize (1) and the litmus 



solution separately, method not given. 

 Use: Determine fermentation of lactose. 

 Variants : 



(a) Smith (1905) gave the following 

 method of preparation. 



(1) Add 10.0 g. of c. p. lactose to 

 1000.0 cc. of sugar free meat infu- 

 sion agar. 



(2) Add 20.0 cc. of a saturated watery 

 solution of lime-free blue litmus 

 to (1). 



(3) Sterilization not specified. 



(b) Heinemann prepared a similar me- 

 dium as follows: 



(1) Add 1.0% lactose to sugar free 

 infusion agar. 



(2) Tube in 8.0 cc. quantities. 



(3) Add 1.0 cc. of 1.0% sterile litmus 

 solution to each tube before using, 



(c) Committee A. P. H. A. (1913). 



(1) Boil 10.0 or 15.0 g. of thread agar 

 in 500.0 cc. of water for half an 

 hour and make up weight to 

 500.0 g. or digest for 15 minutes. 



(2) Infuse 500.0 g. lean meat for 

 24 hours with 500.0 cc. of distilled 

 w^ater in a refrigerator. 



(3) Make up lost weight. 



(4) Strain thru cotton flannel. 



(5) Weigh. 



(6) Add 2.0% Witte's peptone and 

 warm on the water bath until solu- 

 tion is complete. Do not heat 

 above 60°C. 



(7) Mix 500.0 cc. (6) and 500.0 cc. of 



