MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



7. Rinse with distilled water; then stain with Solution F for 

 thirty to fifty seconds. 



8. Differentiate with 95% alcohol; dehydrate; clear in xylol 

 and mount. 



Results: 



Mitochondria are stained red; nuclei, blue. Background, 

 yellow. 



ACID FUCHSIN - PICROINDIGO CARMINE 

 A cytological stain for root tips 



Solutions required: 



A. Acid Fuchsin 1% aqueous 



B. Saturated Picric acid, aqueous . . i volume 

 Saturated Indigo carmine, aqueous i volume 



C. Acetic acid 0-25% aqueous 



Technique: 



1. Bring sections through to distilled water in the usual manner. 



2. Stain from five to twenty minutes in the acid fuchsin solution. 



3. Rinse in water until stain ceases to come out of the sections. 



4. Stain from five to fifteen minutes in solution B. 



5. Wash with solution C. 



6. Wash rapidly in 70% alcohol, in which the sections will 

 appear red. 



7. Wash rapidly in 95% alcohol, until sections appear greenish* 



8. Dehydrate rapidly with two changes of absolute alcohol. 



9. Clear in xylol and mount. 



Results: 



With onion root tips as an example, chromosomes and late 

 prophase stages are in various shades of bright or dark red. Early 

 prophases, bluish red. Nucleoli, clear blue. Spindle fibres and 

 cell walls are stained a dark blue against a light cytoplasm. 



From Plant Microtechnique by D. A. Johansen, by courtesy of McCraw-Hill 

 Book Company, Inc., New York. 



290 



