Chromatin staining reactions by oxidized p-phenylenediamine and Alcian blue

After treatment with oxidized p-phenylenediamine or Alcian blue at high temperature, nuclei from chicken and human blood smears showed an intense staining reaction which proved to be dependent on the DNA content of chromatin. The possibility that oxidized p-phenylenediamine binds to phosphate groups and that Alcian blue interacts with bases of denatured DNA is briefly discussed.