A Combined Toluidine Blue Stain and Mounting Medium

Abstract

A simple combined stain and mounting medium has been in use in this laboratory for a number of years. It consists of an aqueous solution of toluidine blue mixed in suitable concentration with a saturated solution of a water soluble resin. The latter is dimethyl hydantoin formaldehyde resin, marketed by Rex Campbell & Co. Ltd., 7 Idol Lane, East-cheap, London, E.C.3. It has the great advantage that viscosity hardly changes with increasing concentration. A mixture containing the stain can, therefore, be prepared that will remain fluid almost indefinitely if kept in a glass-covered jar, as used for mounting media, but which hardens slowly when exposed to air.