Abstract
Treatment of sections with 9N sulphuric acid at 5°C for 1hr, 18N nitric acid at 60°C for 10min or with 1N or 6N hydrochloric acid at 60°C for 40 and 20min respectively brings about the complete removal of RNA from formalinfixed mammalian tissues as is indicated by methyl green and pyronin staining. Similarly treated sections, when stained with an aqueous solution of toluidine blue O at pH3.0 reveal blue nuclei only, indicating total loss of cytoplasmic basophilia.
