[Proof of the formation of covalent bonds during staining of histologic preparations with procion dyes].

A method proving the formation of covalent bonds between a procion dye and histological slides is suggested based on the splitting of the covalent bound dye (I) into two parts, and on the synthesis of a new dye (II) on one of the parts of the dye (I) which was bound up with a covalent bond. If covalent bonds have not been formed while staining the slides a new dye (II) is not synthesized because two parts of the dye (I) have passed into solution.