slide restoration

[Peter Schuchert]

>Other serious problem is that, a mounting media called entellan (a
>synthetic medium produced by Merck) are used to mount slides (specially
>arthropod-like animals), and I have the experience that passing 2 years,
>the slides begining to show white precipitations inside (similar of your
>problem) and the preparation seems like to broke in a small fragments

Entellan is not suitable for thicker whole mounts, only for thin sections.
I use Eukitt (Merck or Kindler AG, Germany), which is
much more viscous (I even let it concentrate somewhat, so that its
viscosity increases). To avoid cracks or any other deterioration, it
is important not to embed the specimen directly from xylene!
After coloration, ascending ethanol concentration and two xylenes,
I soak the specimens (marine hydroids) first in a xylene/Eukitt
solution (1:1volumes) and then undiluted Eukitt. This, to soak the
specimen with the resin and to remove unnecessay xylene.
Important for sucessful slides is also to use cover slips that are
as small as possible, preferrably circular ones, or rectangular ones cut
to measure.

My oldes preparations made like this are now 7 years and still like
new. Even after several years, the Eukitt can be removed by immersing the
slide in xylene (duration days to weeks), without harming the specimen.

If you have very thick specimens to embed (> 1 mm), or you want
to have them for eternety, you can also use epoxy resins like
Spurr or Durcupan used for embedding in electron micros-
copy (but you won't be able to remove this resin and the procedure
is lengthy).

cheers,
Peter

Peter Schuchert
Museum of Natural History
Dept. of Invertebrates
1, route de Malagnou
CH-1208 Geneva
Switzerland

tel  0041 22 418 64 45
fax 0041 22 418 63 01
http://www.ville-ge.ch/musinfo/mhng/index.htm