[Nhcoll-l] Precipitate or Mold in Ethanol Stored Specimens

[Lazo-Wasem, Eric]

Hi Alex,

This is what happens when a specimen fixed in formalin is not rinsed sufficiently in water before immersion in alcohol.  Depending on the size of the fixed specimen, one needs to wash the specimen for anywhere from a few minutes (small crustacea) to several days (large long fixed sponges, fish, etc.).  I’ve never tested like Judith Price mentions, but the person who hired me several decades ago cautioned me to rinse specimens in water before transferring to alcohol else I can expect precipitate.  It happened enough that I believe his cautionary note without understanding the chemistry.

Best, Eric

Eric A. Lazo-Wasem
Senior Collections Manager
Peabody Museum of Natural History
Yale University
170 Whitney Ave.
New Haven, CT 06520
203 432-3784

From: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> On Behalf Of Alex Krohn
Sent: Tuesday, November 27, 2018 1:53 PM
To: nhcoll-l at mailman.yale.edu
Subject: [Nhcoll-l] Precipitate or Mold in Ethanol Stored Specimens

Hi everyone,

I recently found some bizzare white granules in some our ethanol preserved specimens. See the attached photos. The white granules tend to stick to the items in the jar, rather than rest at the bottom of the jar. They do not crush easily (like I imagine precipitates would), but instead squish more like tiny styrofoam bits or pieces (like I imagine mold would).

Has anyone seen this before? I washed the specimens and jars in fresh 70% EtOH, and then replaced the EtOH in the jar. So far no new granules have appeared. If anyone has any better ideas of what this might be or how to treat it, I'm very interested.

Thank you!

Alex Krohn

---------------------
Assistant Director
Kenneth S. Norris Center for Natural History
University of California, Santa Cruz

https://norriscenter.ucsc.edu/<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fnorriscenter.ucsc.edu%2F&data=02%7C01%7Ceric.lazo-wasem%40yale.edu%7C5666595c09a74e04c5db08d65499e366%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C1%7C636789417298600166&sdata=%2FLFv%2BtstRwFsqjkwGIMX61lFuGgXm028KMCGxSTkjEE%3D&reserved=0>
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