COAL-TAR PLASMA STAINS. 223 



from C. A. F. Kahlbaum's Chemisc,he Fabrik, Berlin, S.C. (Zool. Anz., No. 

 130, 1883, p. 56). Stain essentially that of methyl green, but plasma often 

 violet through the presence of a violet impurity ( MA YES, Mitth. Zool. Stat. 

 Neupel, xii, 1896, p. 311 ; see also earlier editions). 



304. Thiophen Green (Thiophengrun), see KRAUSE, Intern. Monats- 

 schr.f. Anat., etc., iv, 1887, Heft 2. 



305. Anilin Green is said to have a special affinity for mucous gland 

 cells, and other qualities ; but I have not been able to identify the colour 

 mentioned by authors. 



306. Coerulein S., a green dye, is recommended for the staining of 

 muscle-fibrils by M. v. LENHOSSEK (Anat. Anz., xvi, 1899, p. 339). 



307. Quinolein Blue (Cyanin, Chinolinblau ; v. RAXVIEK, Traite, 

 p. 102). Quinolein is said to have the property of staining fatty matters 

 an intense blue. 



It is useful for staining Infusoria, which in dilute solution it stains 

 during life. On this point see the methods of CEETES (post, Part II). 



308. Indulin and Nigrosin. The Indulins are a group of dyes related 

 to the base violanilin. They may be either '' basic" colours or "acid" 

 colours. The soluble indulins of commerce are generally mono- and disul- 

 phonic acids (BENEDiKT and KXECHT, Chemistry of Coal-tar Colours, 

 p. 187). They occur under the brands (not strictly synonyms) of Indulin, 

 Wigrosin, Indigen, Coupler's Blue, Fast Blue R, Fast Blue B, 

 Blackley Blue, Guernsey Blue, Indigo substitute. According to 

 BEHRENS the name Indulin is generally given to a bluish brand, and that 

 of Nigrosin to a blacker one. 



Nigrosin, used with sublimate material, I find stains both nuclei and 

 cytoplasm, the chromatin strongly. I do not consider it a very good plasma 

 stain. It will not give the stain at all with chrom-osniiuui material. 



According to CALBERLA (Morph. Jahrb., iii, 1877, p. 627) the concentrated 

 aqueous solution of Indulin should be diluted with six volumes of water. 

 Sections will stain in the dilute solution in five to twenty minutes; they 

 may be washed in water or in alcohol, and examined either in glycerin or 

 oil of cloves. 



The peculiarity of this stain is said by CALBERLA to be that it never stains 

 nuclei ; the remaining cell-contents and intercellular substance are stained 

 blue. In its general effects it resembles quinolein blue, and is exactly the 

 opposite of methyl green. As far as I have been able to control CALBERLA'S 

 assertions, they appear to me correct ; but I see no special good in it. 



309. EHRLICH'S Indulin-Aurantia-Eosin, or Acidophilous Mix- 

 ture, or Mixture C, or Mixture for Eosinophilous Cells (from the 

 formula kindly sent me by Dr. GRUBLER). Indulin, auraniia, 



