Hoyer's solution

[Nancy Hensold]

Problem: Gum arabic (U.S.P. Flake), a main ingredient in Hoyer's solution*,
is no longer being used by the pharmaceutical industry and is out of
production. The powder form, which is still available, doesn't work. Are
there any Hoyer's users out there who have found a solution to the problem,
or an alternative mounting medium?  There are 2 of us at this institution
who miss it badly.

*"Hoyer's solution" is/was a once-famous mounting medium and clearing agent
popular with bryologists. (Lewis Anderson, The Bryologist 57: 242+. 1954).
I also have used it as a general water-based mount for freehand leaf
sections. I substitute a few drops of phenol as a fungicide and leave out
the chloral hydrate, because then it is even possible to mount stained
material in it. The slides last a very long time, over a year in most cases.
I have had better luck with dissolved gum arabic as a quick and dirty
mounting agent than any of the alternatives, such as glycerin jelly.


Nancy Hensold
Department of Botany
Field Museum
Chicago, IL 60605
hensold at abis.fmnh.org