294 DIFCO MANUAL 



Green Bile Media described in "Standard Methods for the Examination of 

 Water and Sewage"^ and "Standard Methods for the Examination of Dairy 

 Products."^ This dye, in the proper concentration in media, exhibits the desired 

 selectivity, being inhibitive to Gram-positive non-confirming organisms, permit- 

 ting the unrestricted development of the colon-aerogenes group. 



^ Standard Methods for the Examination of 2 Standard Methods for the Examination of 

 Water and Sewage: gth Edition, 1946. Dairy Products, 8th Edition, 1941. 



BAGTO-CRYSTAL VIOLET (B193) 



(Gentian Violet) 



Bacto-Crystal Violent (C.I. No. 681) is certified for use in bacteriological 

 culture media by the Commission on Standardization of Biological Stains. 



Crystal violet and its impure form, gentian violet, have long been used in 

 culture media because of their selective inhibitory action toward the Gram- 

 positive bacteria. Although Bacto-Crystal Violet has a wide range over which 

 it is not significantly toxic to the Gram-negative bacteria and is still definitely 

 bacteriostatic toward the Gram-positive organisms, it should be used with ex- 

 treme care to preserve the proper ratio of dye to medium and to maintain the 

 correct reaction. 



In Tryptose Agar, discussed on page 111, Bacto-Crystal Violet may be used 

 in a concentration of 1 : 700,000 for isolation of Brucella strains from infected 

 milk. Bacto-Crystal Violet is employed in Bacto-Supplement A, a selective 

 enrichment for gonococci and meningococci. A complete discussion of this 

 supplement is given on page 276 or under Bacto-Proteose No. 3 Agar, page 116^ 

 and Bacto-G C Medium Base, page 122. 



BAGTO-EOSIN Y (B194) 



Bacto-Eosin Y (C.I. No. 768) is certified for use in bacteriological culture 

 media by the Commission on Standardization of Biological Stains. 



Bacto-Eosin Y is recommended for use in conjunction with Bacto-Methylene 

 Blue in the preparation of Eosin Methylene Blue Agar according to the Levine 

 formula^ as specified in "Standard Methods for the Examination of Water and 

 Sewage"^ or in accordance with the formula of Holt-Harris and Teague.^ These 

 media are discussed in detail on pages 35 and 133. 



1 Bull. 62, Iowa Eng. Exp. Sta., 1921. ^ j. Infectious Diseases, 18:596:1916. 



2 Standard Methods for the Examination of 

 Water and Sewage, 9th Edition: 187: 1946. 



BACTO-METHYLENE BLUE (B195) 



Bacto-Methylene Blue (C.I. No. 922) is certified for use in bacteriological 

 culture media and for all other purposes by the Commission on Standardization 

 of Biological Stains. 



Bacto-Methylene Blue is recommended for use in conjunction with Bacto- 

 Eosin Y in the preparation of Eosin Methylene Blue Agar according to the 

 Levine formula^ as specified in "Standard Methods for the Examination of 

 Water and Sewage,"^ or in accordance with the formula of Holt-Harris and 

 Teague.^ These media are discussed in detail on pages 35 and 133. 



1 Bull. 62 Iowa Eng. Exp. Sta., 1921. ^ j_ Infectious Diseases, 18:596:1916. 



' Standard Methods for the Examination of 

 Water and Sewage, gth Edition: 187:1946. 



