SECTION TWO 



C. Carbol fuchsin (Ziehl Neelsen) . . i volume 

 Distilled water . . . . • • 9 volumes 



D. Picric acid, saturated, aqueous. 



Technique: 



1. Pieces of tissue are fixed in io% formalin; dehydrated; 

 cleared and embedded in paraffin wax. 



2. Fix sections to slides ; de-wax and take down to distilled 

 water in the usual manner. 



3. Stain in Solution A for about two minutes. 



4. Pour off excess stain and without washing add Gram's 

 iodine and allow the stain to act for one minute. 



5. Differentiate in pure acetone until colour ceases to come out 

 of the sections. 



6. Counterstain in the carbol fuchsin (Solution C) for about a 

 minute. 



7. Pour off excess stain, and drain, without allowing the sections 

 to dry; then without washing: 



8. Cover the sections with the picric acid solution, pouring off 

 after one half to one minute. 



9. Dehydrate and clear with pure acetone for about fifteen 

 seconds. 



10. Clear in xylol and mount. 



Results: 



Gram-positive organisms are stained violet, while Gram- 

 negative are red. Nuclei are stained pink, while cytoplasm is 

 yellow. 



HAEMALUM - EOSIN 

 For demonstrating collagenous tissue 



Solution required: 



A. Haemalum (Mayer). 



B. Eosin, yellowish 0-2% in 20% alcohol. 



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