Janus Green B
Janus Green B is a basic dye and vital stain used in histology. It is also used to stain mitochondria supravitally, as was introduced by Leonor Michaelis in 1900.<ref>Michaelis, L. (1900). Die vitale Farbung, eine Darstellungsmethode der Zellgranula. Archiv für mikroskopische Anatomie 55:558-575(Also Tafel XXXII)</ref>
The indicator Janus Green B changes colour according to the amount of oxygen present.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> When oxygen is present, the indicator oxidizes to a blue colour. In the absence of oxygen, the indicator is reduced and changes to a pink colour.