Effectiveness Of Sch1ff Variants In The Periodic-Schiff and Feulgen Nucleal Technics

Abstract

The presence of additional S02 in Schiff reagents above that required for bleaching of the basic fuchsin has no significant effect on the behavior of such reagents in performing the periodic-Schiff or Feulgen nucleal reactions. Schiff reagents made from aqueous solutions containing less than 0.125% basic fuchsin will not demonstrate in these reactions all the tissue elements stained by stronger solutions. Schiff reagents made from aqueous solutions containing more than 0.5% basic fuchsin will in time precipitate considerable amounts of leucofuchsin. Fresh activated charcoal discriminates much more sharply between the yellow contaminant which occurs in basic fuchsin when the fuchsin has been converted to the leuco state than it does when the fuchsin is in the colored condition. Precipitation of leucofuchsin occurs at pH 3 or slightly above in Schiff reagents of generally useful concentration, but at lower levels down to the pH of 10 N HC1, hydrogen ion concentration does not influence their histochemical effectiveness.