[NHCOLL-L:39] slide restoration

[birger=neuhaus at rz.hu-berlin.de]

Dear colleagues,

reviewing my slide collection of "worms" up to 150 years old I realized 
that an increasing number of slides suffers from different problems:

1. The coverslips of slides some 50-100 years old have disconnected from 
the embedded whole mount. Is somebody aware what kind of embedding medium 
was used commonly at that time in Germany, Europe, or the USA? Is it 
possible to identify the embedding medium in one way or another easily?
2. The embedding medium (might be canada balsam) has withdrawn from around 
the specimen leaving the specimen in a cavity. Is there any possibility to 
re-embed specimens?
3. Slides from the rotifer collection of Charles Rousselet (slides made 
around 1910) show white precipitations in the periphery of the sealed 
coverslip. The embedding medium is glass-clear and not yellowish as in 
other material from that time.
4. Slides occasionally break apart, and we try to glue together major parts 
with a glass-clear 2-component epoxid resin (Henkel: Pattex Kraft-Mix).
5. Which embedding medium/procedure would you recommend for permanent 
slides of fresh specimens of a) Crustacea and b) "worms" such as Polychaeta 
or Nematoda? Sealed paraffin-glycerin mounts as commonly used for nematodes 
probably require regular (yearly?) inspection intervals to check the 
quality of the slides?

I have looked through several books on the preservation of natural history 
collections, but did not find hints to how to solve problems as mentioned 
above. I would greatly appreciate your comments, suggestions, hints to 
published references, ...

Birger Neuhaus

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Dr. Birger Neuhaus
Museum fuer Naturkunde
Institut fuer Systematische Zoologie
Invalidenstr. 43
D-10115 Berlin
Germany
Tel.: +49 (0)30 2093 8525
Fax: +49 (0)30 2093 8528
e-mail: birger=neuhaus at museum.hu-berlin.de