Mountant control on glass.

Some microscope slide mountants exhibit a tendency to spread beyond the periphery of their cover slips, flowing over the edge and under the slide, fouling the stationary and moving components of the mechanical stage. In the authors' experience, mountants that are most commonly associated with this problem are alcohol, lactophenol, water and other water-soluble preparations of low viscosity. The p r o b l e m of mountant control is particularly bothersome in examination of water mounts using the compound microscope. After many years of living with the problem, a method has been found that will control droplet size and prevent mounting preparations from flattening and creeping in an uncontrolled manner across the length and width of a microscope slide. Glass slides are treated with Siliclad ®, a silicone preparation marketed by Clay Adams Co. The process is relatively simple and the coating is reasonably long.lasting. Glassware to be treated is washed, then rinsed in clear deionized water. It is then immersed for 5 sec in a solution of 1 part Siliclad to 100 parts water. The silicone-coated glass must undergo a curing period at 100 C for 10 rain, or at room temperature for 24 hr. At the time of this writing, treated slides which have been used repeatedly for temporary water mounts almost