The present investigation comprised 171 eyes examined in the slit lamp and 99 specimens of mucous thread, epithelial scrapings, and conjunctival fluid subjected to microscopy after vital staining by lissamine green, in most cases combined with rose bengal. Lissamine green is suitable for vital staining of cornea and conjunctiva. The dye stains degenerate cells, dead cells and mucus. Its vital‐staining properties are almost identical with those of rose bengal. If used successively, the primarily employed component will predominate over the other. A mixture of lissamine green and rose bengal constitutes a blue, stable vital stain yielding mainly a blue colour, although green and red may also be seen. On the average, 70.5 % of the mucous thread is stained blue, 20.1 % green, and 9.3 % red, the zones of different colours alternating along the length of the thread.
M. S. Norn (Wed,) studied this question.