Elastic fibers were stained with alum hematoxylins adjusted to near neutral pH, and the characteristics of modified alum hematoxylin in the staining of elastic fibers were examined and compared with those of conventional elastic fiber stains.
Cartilage and sublingual mucous cells were strongly stained with orcein, resorcinfuchsin, but not with modified alum hematoxylin, the latter showed an affinity for surface epithelial mucous cells of the stomach. In model tissue-experiments using synthetic polyamino acids, modified alum hematoxylin did not exhibit an affinity for tyrosine, whereas orcein, aldehyde-fuchsin, resorcin-fuchsin, and iron-hematoxylin did.
These findings and the results of various blocking reactions prior to staining, suggest that modified alum hematoxylin does not possess basic dye characteristics. The staining mechanisms of modified alum hematoxlin and conventional elastic fiber stains are discussed.