Nitro and Azo Dyes 89 



Dl5 BIEBRICH SCARLET, WATER SOLUBLE C. I. NO. 2.8o 



Synonyms: Croceine scarlet. Scarlet B, or EC. Ponceau B. 



Double scarlet BSF. 



C22Hi4N407S2Na2; Mol. Wt. 556.478 

 {An acid dye; absorption maximum about 503.5) 

 Solubility at 26°C: in alcohol 0.05% 



The chief biological application of this dye is for medicinal pur- 

 poses, but it is occasionally used as a plasma stain, notably for 

 tissues after staining with polychrome methylene blue or Unna's 

 hematein. It has also been made use of by Paladino (1895) mixed 

 with alum hematoxylin for double staining effect on histological 

 material. In a neutral stain combination with ethyl violet, it has 

 been employed by Bowie (1924) for staining the islets of Langer- 

 hans. More recently it has been recommended by Lillie (1940) in 

 the Masson trichrome technic, by Schoor (1941) in combination 

 with orange G and fast green FCF for staining vaginal smears; 

 while McFarlane (1944) uses it in the modification of the Mallory 

 stain which he terms "Picro-Mallory". 



For use of Biebrich scarlet with plcro-aniline-blue, or with methyl blue, see 



Staining Procedures, p. IB3-I2. 



For technic of Masson trichrome stain, Lillie modification, see Id. p. IB3-I8. 



Dl6 PONCEAU S. C. I. XO. iSl 



Synonym: Fast ponceau 2B. 



OH 



I 

 NaS03_/~X_N = N_/— \_N = N_/~\ 



\_/ \_/ v ■ 



CH3 \_ 



C23Hi7N404SNa; Mol. Wt. 468.282 

 {An acid dye) 



Reference to this dye in biological literature shows a rather un- 

 usual history. It was mentioned quite early by Curtis (1905) who 

 found it an improvement over acid fuchsin in the \ anGieson stain. 



