NUCLEAL REACTION: Feulgen's modification of the Schiff reaction for 

 aldehydes. _A. Water with an excess of sulfur dioxide. Water 200 ml., 

 sodium bisulfite 1.3 g., IN hydrochloric acid 10 ml. B. Fuchsin- 

 sulfurous acid reagent . Dissolve 1 g. of basic fuchsin in 100 ml. warm 

 water. Filter. Add 20 ml. of 1 N hydrochloric acid and 1 g. sodium 

 bisulfite. Let stand 24 hours. Decolorize with Norite and filter. 



PARACARMINE: (Mayer's) Carminic acid 1 g., aluminum chloride 0.5 g. , 

 calcium chloride 4 g., 70% alcohol 100 ml. Dissolve and allow to settle. 

 Filter, 



PICRO-CARMINE: Cone, ammonium hydroxide 5 ml., water 50 ml., carmine 

 1 g. When dissolved add saturated aqueous picric acid SO ml. Expose 

 to air and light for 2 days, then filter. 



PICRO- FUCHSIN: (Van Gieson) Acid fuchsin (1% aq. sol.) 10 ml., 

 picric acid (sat. aq. sol.) 90 ml. 



POLYCHROME METHYLENE BLUE: (for staining cell granules) 

 Michaelis ' method : Methylene blue 2 g. , water 200 ml. To this solution 

 add 10 ml. of 0.1 N sodium hydroxide. Boil for 15 minutes. After cool- 

 ing add 10 ml. of 0.1 N sulfuric acid and filter. 



POLYCHROME METHYLENE BLUE: Unna's method : Methylene blue 1 g. , potas- 

 sium carbonate 1 g., 95% alcohol 20 ml., water 100 ml. Evaporate to 

 100 ml. It may be used at once, or after diluting with an equal volume 

 of anilin water. See Chapter III. 



SCHARLACH R: 70% alcohol 50 ml., acetone 50 ml., Scharlach red to 

 saturation. 



THIONIN, ACID: (Frost's form) Thionin 1 g. , phrenol 2.5 g. , glacial 

 acetic acid 20 ml., water 400 ml. 



TRIACID STAIN: See Erlich's triple stain. 



UNNA-PAPPENHEIM STAIN: (modified) Pyronin Y 0.9 g. , methyl green 

 0.1 g., 95% alcohol 9 ml., glycerine 10 ml., 0.5% phenol to 100 ml. 



WEIGERT'S STAIN: (for elastic tissue) (resorcin-fuchsin) Basic 

 fuchsin 2 g. , resorcinol 4 g. , water 200 ml. Heat the mixture in a 

 porcelain dish and while boiling add 25 ml. of a 29% aqueous solution 

 of ferric chloride (FeCl3»H20). Stir and boil for 2-5 minutes. A pre- 

 cipitate forms. Filter. Discard the filtrate. Drain the filter paper 

 dry and return the paper and precipitate to the dish. Add 200 ml. of 



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