SECTION TWO 



Technique: 



1. Tissues are fixed in Regaud's fluid, washed in running water, 

 dehydrated, cleared and embedded in paraffin wax as usual. 



2. Fix sections to slides; de-wax; pass through the alcohol 

 down to distilled water in the usual manner. 



3. Stain in the methylene blue solution for twelve to sixteen 

 hours. 



4. Decolorize with 95% alcohol. 



5. Counterstain with the basic fuchsin solution for fifteen min- 

 utes. 



6. Decolorize for one to three seconds in the citric acid solu- 

 tion. 



7. Pour off excess citric acid ; rinse in distilled water; drain and 

 blot carefully. 



8. Decolorize and dehydrate rapidly in absolute alcohol. 



9. Clear in xylol and mount in dammar xylol. 



Results: 



Rickettsia are stained a deep red; surrounding tissue, pink; 

 background, light blue. 



METHYLENE BLUE POLYCHROME (Unna) 

 For mast cells in sections 



Solutions required: 



Methylene blue, polychrome 



(Unna) . . . . . . 100 ml. 



Potash alum . . . . • • 5 gm. 



Technique: 



1. Material is fixed in absolute alcohol and embedded in 

 Celloidin. 



2. Stain sections in a watch glass from three to sixteen hours in 

 the methylene blue solution. 



3. Rinse well in distilled water. 



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