, Volume 64, Issue 2, pp 119–130

Orcein, collastin and pseudo-elastica: a re-investigation of Unna's concepts

  • Holde Puchtler
  • Susan N. Meloan

DOI: 10.1007/BF00490093

Cite this article as:
Puchtler, H. & Meloan, S.N. Histochemistry (1979) 64: 119. doi:10.1007/BF00490093


Orcein has been recommended for identification of elastin. Since other traditional elastica stains proved to be unspecific, it was deemed of interest to determine the selectivity of orcein and to review pertinent literature.

Orcein was employed as a textile dye in ancient Egypt and was used for dyeing of wool and silk until the early 20th century. It was introduced into histological technic in 1878 as a stain for cytoplasm. Unna recommended it for demonstration of elastic tissue in 1890 and retracted claims for its specifity in 1894 because orcein colored also certain collagen fibers. Unna suggested the term collastin for collagen fibers which share the affinity of elastin for acid orcein. Other orcein solutions were used as selective stains for collagen.

In histochemical studies, the staining properties of resorcin-fuchsin and orcein were very similar; elastin and various collagen fibers were strongly colored. Unna's collastin is apparently identical with the pseudo-elastica described in sections stained with resorcin-fuchsin. Both dyes react with meshworks of fine fibers, embryonic, experimentally or pathologically altered collagens. It is suggested to use the term collastin, instead of pseudo-elastica, for collagenous fibers which bind the traditional elastica stains.

Copyright information

© Springer-Verlag 1979

Authors and Affiliations

  • Holde Puchtler
    • 1
  • Susan N. Meloan
    • 1
  1. 1.Department of PathologyMedical College of GeorgiaAugustaUSA