A Substitute for Glycerine as a Mounting Medium

Abstract

FIFTY percent glycerine which is widely used as a temporary mounting medium for sections of plant tissues is now difficult to get. Instead, a nearly saturated solution of calcium chloride can be tried. Put excess of commercial calcium chloride in tap water, remove the slight amount of chalk with hydrochloric acid, let any bits settle and filter if necessary. This solution is rather similar to 50 percent glycerine in viscosity, refractive index and, of course, will not dry up. At pre-war rates it is a good deal cheaper than 50 percent glycerine. It can be used in just the same way as glycerine with such stains as iodine, Sudan III, alcoholic phloroglucin (but not alkalis or sulphates). If the bulk of the calcium chloride is removed by washing the section in water or alcohol for a moment, it can be stained and dehydrated in the ordinary way.