72 Biological Stains 



cll BENZENE-AZO-a-NAPHTHYLAMINE 



/\_N_N_/~"V_NH2 



C16H13N3; Mol. Wt. 247.288 

 {Absorption maximum of hydrochloride 557.6 in alcohol) 



A colored compound recently employed by Carter (1933) as a 

 vital stain for protozoa (probably in the form of its hydrochloride) 

 and given the abbreviated name "BAN". This product has ap- 

 parently never been put on the market as a commercial dye; only 

 its formula and chemical properties are known. 



cl3 ORANGE G C. I. NO. ly 



Synonym : Wool orhnge 2G. 

 Slightly different grade: Orange GG, GMP. Crystal orange GG. 



SOsNa 



/\N = N_ 1 



\/ H0-| 1 ] 



SOsNa 

 Ci6HioN207S2Na2; MoL Wt. 452.370 



{An acid dye; absorption maximum about 476-4-80) 

 Solubility at 26°C: in water 10.86%; in alcohol 0.22% 



This dye is strongly acid because of the two sulfonic groups. 

 It is one of the most valuable plasma stains in histological work. 

 It has great use as a background stain for hematoxylin and other 

 nuclear dyes in cytology. It is frequently employed, both by 

 botanists and zoologists, as a cytoplasmic stain, together with the 

 two nuclear dyes safranin and gentian violet in the Flemming triple 

 stain. It is of importance to the pathologist for its use with anilin 

 blue and acid fuchsin in the Mallory connective tissue stain; and 

 is used in various other double and triple staining methods, such 

 as that of Ehrlich-Biondi-Heidenhain, in which it is mixed with 

 methyl green and acid fuchsin. The Ehrlich "triacid mixture," 

 also a combination of these same three dyes, is used in staining 

 blood. A further use is Bensley's "neutral gentian," a combi- 

 nation of orange G and gentian violet for staining the A and B cells 

 in the islands of Langerhans. An important recent application is 

 by Stoughton (1930), with thionin, for the differentiation of para- 

 sites in plant tissue. 



