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; dewax; 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 Clearmount or D.P.X. 



Results: 



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

 background, light blue. 



Reference: Zinsser, H., Fitzpatrick, F. & Hsi Wei (1939). 



METHYLENE BLUE, LEUCO 



For the differential cytophysiological diagnosis of 

 cancerous and normal tissues 



Solutions required: 



A. Hyposulphite leuco base of methylene 

 blue (HLM) 

 Methylene blue, o-i% aqueous. . 10 ml. 



Note: This should be prepared with fresh, double 

 distilled water. 

 Sodium thiosulphate (Na2S203, 



5H2O), A.R 0-8 gm. 



303 



