MILK MEDIA EGG MEDIA 51 



LXXXII. DUNHAMS PEPTONE SOLUTION. 



Dried peptone ... 1 gramme. 



Sodium chloride . . . 0'5 



Distilled water . . .100 c.c. 



Filter, place in tubes, and sterilize by the ordinary discontinuous 

 method for three successive days. 



This solution is used as a medium to determine if an organism 

 under consideration possesses the property of producing indol as one 

 of its products of nutrition. 



LXXXIII. PEFIONE ROSOLIC ACID SOLUTION. 



Dunharrfs peptone solution . . 100 c.c. 



and 2 c.c. of the following solution : 



Rosolic acid (Coralline) . . 0.5 gramme. 



Alcohol (80 per cent.) . . 100 c.c. 



are boiled, filtered, placed in test-tubes, and sterilized by the ordinary 

 discontinuous method for three successive days. This medium is used 

 to study the reactions produced by different bacteria. 



MILK MEDIA. 



LXXXIV. The milk must be quite fresh and the reaction must 

 not be acid. Place about 10 c.c. in each tube, plug, and sterilize in 

 steam sterilizer for one hour on each of three successive days. When 

 the tubes are not in the sterilizer they must be kept at about 20 C. 



The sterilization of milk media is very important, as the spores of 

 some of the milk bacteria are most resistant. 



LXXXV. Milk media for testing the reactions of certain 

 bacteria are prepared by adding a few drops of tincture of litmus to 

 the medium before sterilization until it is slightly blue in colour. 

 Ordinary milk media acquires a light brown colour after sterilization. 



EGG MEDIA. 



LXXXVI. HUEPPE'S METHOD. 



1. Wash a fresh egg with a brush and soap and water. 



2. Sterilize a glass dish with sublimate solution, wash with 

 sterilized water, and dry with sterilized wadding. 



