Abstract
Acidic and basic dyes react preferentially with the mucoproteins of beef corneal stroma. Free carboxyl groups of the mucoproteins can combine readily with cations; additional reaction with ions seems to involve an unmasking of charged groups in these proteins. Most of the dyes studied apparently react as aggregates in 0.02 M solution, and are fully dissociated only in much more dilute solution. The state of aggregation of methylene blue has a pronounced effect on the affinity with which this dye combines with the tissue, but the chemical reaction is limited, nevertheless, to the corneal mucoproteins.