orcein

It is then converted to orcein by ammonia and air.

They have been important in history, because they could supply orcein, a dye.

Often orcein or a combination of resorcinol and fuchsine are used for staining.

It changes readily into orcein.

The chemical components of orcein were elucidated only in the 1950s by Hans Musso.

In contrast with orcein, the principal constituent of litmus has average molecular weight of 3300.

HOPS is an acronym for haematoxylin, orcein, phyloxin and saffron.

Most of the chemical components of litmus are likely to be the same as those of the related mixture known as orcein, but in different proportions.

It is used in the production of the dye orcein and as a reagent in some chemical tests for pentoses, such as Bial's Test.

Elastic fibers stain well with aldehyde fuchsin, orcein, and Weigert's elastic stain in histological sections.

Oxidation of the ammoniacal solution gives orcein, CHNO, the chief constituent of the natural dye archil.

Unlike Oxytalan fibres, elaunin fibres stain with orcein, aldehyde fuchsin and resorcin fuchsin without prior oxidation.

Orcein began to achieve popularity again in the 19th century, when violet and purple became the color of demi-mourning, worn after a widow or widower had worn black for a certain time, before he or she returned to wearing ordinary colors.

The spread nuclei can be simply stained in acetic orcein (Gurr) under a coverslip and if the staining is slow, or the slides are to be kept for a short time, the coverslips can be ringed with rubber solution (Weldtite) to prevent the stain drying out.

A paper originally published in 1961, embodying most of Musso's work on components of orcein and litmus, was translated into English and published in 2003 in a special issue of the journal Biotechnic & Histochemistry (Vol 78, No. 6) devoted to the dye.