INGREDIENTS OF CULTURE MEDIA 299 



MISCELLANEOUS INGREDIENTS 



BAGTO-EGG ALBUMEN, GOAGULATED (B147) 



BAGTO-EGG YOLK, GOAGULATED (B148) 



BAGTO-WHOLE EGG, GOAGULATED (B149) 



At the suggestion of, and in cooperation with, R. S. Spray, we have prepared 

 Bacto-Egg Albumen, Coagulated; Bacto-Egg Yolk, Coagulated; and Bacto-Whole 

 Egg, Coagulated. In his extensive studies on the use of egg for the cultivation 

 and differentiation of anaerobic bacteria Spray^ used these dehydrated egg prod- 

 ucts with excellent results. 



Bacto-Egg Albumen, Coagulated is free from all traces of egg yolk. Bacto- 

 Egg Yolk, Coagulated is similarly free from traces of egg albumen, while Bacto- 

 Whole Egg, Coagulated, as the name indicates, contains both of these materials. 

 All three are prepared for use by making a suspension of 0.5 gram of material 

 in 10 ml. of distilled water or Nutrient Broth in a test tube. Spray has also 

 found that a solution of Bacto-Tryptone was distinctly advantageous as a diluent 

 for these materials. The suspensions are sterilized by autoclaving for 15 minutes 

 at 15 pounds pressure (121°C.). After sterilization the media will have a reaction 

 of pH 7.2 and will present a loosely flocculent appearance with a layer of fluid 

 above the solid material. 



The tubes are inoculated deeply by loop or pipette. Characteristic reactions 

 indicative of proteolysis are produced by most anaerobes. The addition of re- 

 duced iron or lead acetate to the media greatly intensifies the blackening of the 

 media produced by the action of proteolytic organisms. 

 1 J. Lab. Clin. Med., 18:512:1932-33. 



BAGTOJSOELEGTRIG GASEIN (B145) 



Bacto-Isoelectric Casein is a protein of exceptional purity, prepared by re- 

 peated precipitation of casein at its isoelectric point. This casein of more than 

 ordinary purity is recommended for use in routine bacteriological culture media 

 and also for the most exacting special procedures. It is suitable for the Fuld 

 Gross method for the determination of tryptic activity. Bacto-Isoelectric Casein 

 is quickly and completely soluble in a concentration of 1-2 per cent in a slightly 

 alkaline solution. 



Sodium caseinate is readily prepared by suspending Bacto-Isoelectric Casein 

 in water for a few minutes and then making the suspension slightly alkaline with 

 sodium hydroxide. This alkaline condition should be maintained until solution 

 is complete. When prepared in this manner the solution of Bacto-Isoelectric 

 Casein is light in color and only lightly opalescent. 



GASEIN PURIFIED, DIFGO (B336) 



Casein Purified is recommended for all procedures requiring a casein of high 

 purity. Repeated precipitation and washing of casein at the isoelectric point 



