position, it has similar physical properties and is fat soluble. It is, 

 therefore, one of the best fat stains knoTVTi. 



BIEBRICH SCARLET, WATER SOLUBLE C. I. NO. 280 



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



Double scarlet. 



X = X 



" r{ X 



/\/ I I H0_ 



xXaS03 /\/ 



XaSOj N = N 



{An acid dye; absorption maximum about 503.5) 



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 

 haematein. It has also been made use of bv Paladino mixed with 

 alum haematoxylin for double staining effect on histological, 

 material. 



BISMARCK BROWN Y C. I. NO. 33 I 



Synonyms: Ve.suvin. Phenylene brown. Manchester brown. 

 Excelsior brown. Leather brown. 



Slightly different shade: Bi-wiarck broivn G. 



To be distinguished from :Bismark brown R or GOOO (C. I. No. 

 332.) 



{An acid dye.) 



The various shades of Bismarck bro\\Ti are mixtures of different 

 compounds, the most important of which are salts of the following: 



XH2 



This dye was formerly employed quite extensively as a contrast 

 stain, but has now been replaced to some extent by others. It is 

 still used, however, as a mucin stain, and is good for vital staining 

 and for staining in bulk. It is employed in staining cellulose walls 

 of plants in contrast to haematoxylin; and occasionally for staining 

 bacteria in contrast to gential violet in the Gram technic. 



39 



