[Nhcoll-l] Formalin in exhibition instead of ethanol

[John E Simmons]

A few caveats about glycerin:

Before committing to putting a large squid in glycerin, you should test how
it will behave due to the difference in density between alcohol (0.890
g/cm3) vs. glycerin (at 100%, it is 1.26 g/cm3, though of course diluted to
60% will be a bit less). This may be important due to the density of the
specimen itself compared to the density of vertebrate specimens stored in
glycerin.

As you work on the design for the new exhibit, don't forget that due to its
density, the volume of glycerin will be a lot heavier than a similar volume
of alcohol. In a large aquarium-type exhibition this weight difference may
affect seams and seals.

Lastly, mold in the glycerin is not the only thing you have to worry
about--don't forget bacterial infestations. Using some sort of biocide as a
preventive measure may be necessary (traditionally thymol has been used,
but as Simon Moore has pointed out, you can use less dangerous chemicals
such as camphor as well). The other aspect of contamination is that if the
seal on the container is faulty so that it admits mold spores or bacteria,
in a humid environment the hygroscopic glycerin can absorb enough moisture
to overflow the container. In a previous job I had to to take care of a
collection of about 3,000 cleared-and-stained specimens stored in glycerin,
and even though there was next to no loss due to evaporation, during a
humid summer we could always count on a few containers overflowing (we had
no mold or bacterial issues becaused thymol as a biocide).

--John

John E. Simmons
Writer and Museum Consultant
Museologica
*and*
Associate Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
*and*
Investigador Asociado, Departamento de Ornitologia
Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima


On Fri, Feb 4, 2022 at 12:47 PM Dirk Neumann <neumann at snsb.de> wrote:

> Hi Bo,
>
> maybe a comment pointing into a slightly different direction (similar to
> what colleagues did in Berlin), as you mentioned you are planning for a
> major renovation of your exhibitions:
>
> An alternative would be to have a cabinet that is "inaccessible" for
> visitors and equipped with necessary installations to comply with
> fire-safety regulations (like a tank in an public aquarium). Thus the
> specimen would be visible for the visitors, the container as such however
> would not be part of the publicly accessible visitor space. This could help
> to avoid transferring the specimen into a different fluid, potentially
> causing secondary conservation problems.
>
> At the MfN in Berlin they used this alternative to make the fluid
> collections accessible and discoverable for visitors, while keeping the
> visitor and collection space simultaneously strictly separated. They also
> used this concept for a huge glass cabinet that shows a large diversity of
> collection objects on display, including fluid-preserved specimens.
>
> Maybe worth a thought ...
>
> With best wishes
> Dirk
>
>
> Am 04.02.2022 um 16:40 schrieb Bo Delling:
>
> Hi again,
>
>
>
> Thank you all for detailed and interesting information on this topic.
> Glycerol seems to be very interesting making nice specimens for exhibitions
> if you have fresh specimens with nice color. I will try it in the future
> for some small richly coloured fish. Is it correct that if you keep the
> concentration at 65% you don’t run in to problems with mould?
>
>
>
> Regarding our squid(s) they aren’t that nice and if we can’t continue with
> ethanol I think we transfer selected specimen to a formalin solution after
> all (Jon, thank you for the publication with relevant references). James, I
> will check if we have any pictures and size estimates. The length of the
> mantel is about 1 m for both specimens. Ironically, the one we had for
> display is the one in worst condition (in several pieces, semi rotten I
> would say) collected close to Scotland around 1990 or so. The other one was
> collected by a shrimp trawler from Sweden in 1960 and this specimen have
> commonly been referred to as “the green squid” . Initially it was stored in
> a tank made of cupper. Nevertheless it’s in much better physical condition
> and consequently we will continue having a giant squid on display but not
> the same specimen.
>
>
>
> Cheers,
>
>
>
> Bo
>
>
>
>
>
> *Från:* Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu>
> <nhcoll-l-bounces at mailman.yale.edu> *För *Bo Delling
> *Skickat:* den 3 februari 2022 12:15
> *Till:* 'nhcoll-l at mailman.yale.edu' <nhcoll-l at mailman.yale.edu>
> <nhcoll-l at mailman.yale.edu>
> *Ämne:* [Nhcoll-l] Formalin in exhibition instead of ethanol
>
>
>
> Dear all,
>
> Up to recently we had a giant squid *Architeuthis *sp*. *in exhibition
> (“Liv in Vatten” = Life in Water/Aquatic life). It was contained in an
> aquarium, 80% ethanol (650 liters!). For the moment, we are planning for
> thorough modernization, i.e. the exhibition will be rebuilt from scratch
> but we wish to keep the squid. It is very popular. However, we might face
> problems regarding fire safety regulations and one idea that came up was to
> transfer the specimen to weak formalin solution (1%).
>
> -Anyone having any experience and perhaps suggestions regarding
> concentration and suitable buffer?
>
> My limited experience is based on museum specimens (mainly fishes) that
> previously were in the old NRM exhibitions. I come across them now and then
> in the scientific collection and according to older documents, the ethanol
> was replaced with formalin around 1960 because the expense. Anyway, this
> old exhibition jars with specimens look very nice (except for bleaching of
> specimens) and the fluid (formalin solution) looks like clear water.
>
> All the best,
>
> Bo
>
>
>
>
>
> Bo Delling, PhD Ichthyology
>
> Curator of Fishes and Herptiles
>
>
>
> Swedish Museum of Natural History
>
> Department of Zoology
>
> Frescativägen 44
>
> P.O. Box 50007
>
> SE-104 05 Stockholm
>
>
>
> Phone: +46 85195 4240
>
>
>
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> --
>
>
> Dirk Neumann
>
> Tel: 089 / 8107-111
> Fax: 089 / 8107-300
> neumann(a)snsb.de
>
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>
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>
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>
> ---------
>
> Dirk Neumann
>
> Tel: +49-89-8107-111
> Fax: +49-89-8107-300
> neumann(a)snsb.de
>
> postal address:
>
> Bavarian Natural History Collections
> The Bavarian State Collection of Zoology
> Dirk Neumann, Section Ichthyology / DNA-Storage
> Muenchhausenstr. 21
> 81247 Munich (Germany)
>
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