MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



2. Differentiate in i% nitric acid. 



3. Dehydrate in acetone; mount. 



Results: 



Epidermis, yellow. Cortex, yellow. Pericycle (lignified tissues), 

 blood red. Zylem, salmon to blood red. Primary phloem, orange. 

 Cambium, pale yellow. Secondary phloem, crimson. Sieve plates, 

 some very bright crimson, others orange. Pith, amber. 



Abstract: (1947) Stain Tech., VoL 22, 4, 155-6, B. Vercourt. 



COTTON BLUE - SAFRANIN 

 For fungal h3rphae in woody tissues 



Solutions required: 



A. Cotton blue 0-5% in Lactophenol. 



B. Lactophenol. 



C. Safranin 1% aqueous. 



Technique: 



1 . Stain thin sections with solution A, which has been warmed to 

 about 35° C, for five to fifteen minutes. 



2. Wash with Lactophenol to remove excess stain. 



3. Wash with 70% alcohol to remove Lactophenol. 



4. Counterstain with the safranin for about ten minutes. 



5. Wash with 70% alcohol taking care that the safranin is not 

 entirely removed. 



6. Rinse rapidly in 90% alcohol. 



7. Dehydrate with absolute alcohol. 



8. Clear in xylol. 



9. Mount in Canada balsam in xylol or in Cristalite. 



Results: 



Fungal hyphae, blue. Xylem, red. 



Reference: Chesters (1934), Ann. Bot., 48, 820. 



