134 Biological Stains 



stain, and by Kultschitzky for staining elastic tissue. No infor- 

 mation is available, however, as to whether they used phloxine or 

 true magdala red. 



c. The Indulins 



Indulins are similar to safranins but are more complex: being 

 quite highly phenylated amino derivatives. Only a few concern us. 



'-40 INDULIN, SPIRIT SOLUBLE C. I. NO. 86o 



Synonyms: Indulin (with various shade designations). Spirit 



indulin. Spirit nigrosin R. 



This consists of mixtures of the following: 







HN_/\_N_/\_NH , /\_N_/V_NH 



I J I J and •HN_| J f J 



HN-\/-N=\/-NH I \/— N=\/-NH 



" ^ " 6 



C42H33N6CI; Mol. Wt. 657.189 CseHzsNgCl; Mol. Wt. 566.081 



{A basic dye; absorption maximum varies from 54-1.5 to 560.5) 



l45 indulin, water SOLUBLE * C. I. NO. 86 1 



Synonyms: Indulin (with various shade designations). Soluble 

 indulin SB. Fast blue B, OBy R, 2R, etc. 



{An acid dye) 



This is the sodium salt of the sulfonation product of indulin, 

 spirit soluble (C. I. No. 860). Because there are various mixtures 

 of the latter and different degrees of sulfonation are possible, this 

 dye may vary greatly in its composition and shade. 



One of the indulins (exact nature uncertain) has been used by 

 Lynch (1930) in the counterstaining of bulk tissue; also by Cum- 

 ley (1935) in the negative staining of bacteria. For the latter pur- 

 pose, however, the following dye is more commonly employed. 



