The Mounting of Carbowax Sections with Lighter-Fluid and Rubber Cement

Abstract

Serial sections cut from plant tissues embedded in Carbowax have been affixed to slides with rubber cement. A rather thick layer of undiluted rubber cement was first spread on the slides. The Carbowax ribbons were added next. Lighter-fluid, essentially petroleum ether which can be substituted for it, was then run under the sections to dissolve the rubber cement and to float the ribbons. This flotation medium did not dissolve the Carbowax and the ribbons could be manipulated in it for accurate location. The slides were dried on a 45[degree]C warming table which also helped to flatten the sections. Adhesion was best when drying times were held to 4 hr or less. All excess rubber cement was washed away with xylene immediately prior to covering and the cover slips were carefully applied with a very thin resinous mounting medium to prevent dislodging the sections. Both aqueous and alcoholic stains have been used successfully and the slides have been left in them for as long as 3 days without loss of sections. The method was developed for fluorescence microscopy but serves equally well for visible light microscopy. Slides stained with a safranin-fast green combination have been used for both purposes, the safranin staining and fluorescing in a manner similar to rhodamine B.