eosins

The substances utilized with but few exceptions for red ink are the "eosins," possessing different names like erythrosine, as well as different hues.

Forty Centuries of Ink 1904

When watery solutions of medicinal methylene blue and water soluble eosins are mixed a precipitate is formed which is soluble only in alcohol, and solutions of this precipitate impart a peculiar reddish-purple colour to chromatin.

The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged.

Particularly fugitive are the eosins, and yet some of these, by a slight modification of constitution, e.g., the introduction of an ethyl group, as in ethyl-eosin, are rendered distinctly faster.

Scientific American Supplement, No. 810, July 11, 1891 Various