<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<p>Dear Esther, dear Marion,</p>
<p>Sorry for the late response, very interesting topic indeed. </p>
<p>I have transferred a few collections into glycerol with very good
results (i'm currently working on another collection doing this at
the moment). My first try was done by a simple protocol that I got
from Andries van Dam back in 2018, after he presented the use of
Glycerol as a alternative preservation fluid at the PFC2018 in
Paris. The use of glycerol goes back to the times of Carl
Kaiserling (1869-1942) and Leonhard Jores (1866-1935), both German
pathologists that presented their potential as preservation fluid
over 120 years back in the field of anatomical preparation.
Besides a few publications from Andreis van Dam (Maclead & Van
Dam 2011; Van Dam 2020), there is not much resent research into
this mater that i'm aware of. I will hopefully be able to publish
something in a soon future. Andries and I did a nice presentation
at a meeting organized by the German conservators/restorers
society (VDR) last year, but there is no real conference paper
available.<br>
</p>
<p>
</p>
<p>The glycerol solution concentration is crucial, specimens have to
be transferred into a 65% solution of glycerol in water. By this,
the mentioned absorption of humidity is inhibited since the
solution is "saturated" with water and there should be no
absorption of water from the environment. Glycerol solution with
much higher content of glycerol (80-95%), can indeed absorb
moisture from the surrounding environment, specially if poorly
sealed. But if the transfer in steps into 65% of glycerol is made
correctly, there is no need for any kind of fungicide in the
preservation fluid. This is actually the biggest advantage of
using glycerol in the first place (besides fire hazards, toxicity
issues and/or evaporation), since it enables the use of a toxin
free preservation fluid. Cleared specimens stored in higher
glycerol concentrations, can be transferred into a 65% glycerol
solution as well. Other mentioned issues like the slight color
change, are of course things to be taking into account before the
transfer. Besides that it is a really sticky job.<br>
</p>
<p>Important things to take account are: big specimens that will
take a long time to transfer from one step into another; a very
good plan of transfer between fluids, since specimens will take
different amount of time to transfer depending on their volume;
the size of the receptacles for the transfer, since a good
transfer requires a much higher ratio of fluid to specimen in
order to enable a fast diffusion of the fluid; and of course the
final container, since a good sealing is essential for the
preservation of fluid preserved specimens. <br>
</p>
<p>I would be super happy to provide you with a protocol, even tough
this has to be adapted to the specific collection, depending on
specimen size, tissue type and so on. Just let me know.</p>
<p>All the best,<br>
</p>
<p><br>
</p>
<p>Literature cited: <br>
</p>
<p>Van
Dam, A.: Finding a cure for hazardous collections: the road to
zero formaldehyde and ethanol. In: Collection Forum (34). 2020. S.
118–123.
</p>
<div
style="language:de;margin-top:0pt;margin-bottom:0pt;margin-left:.31in;
text-indent:-.31in;text-align:justify;text-justify:inter-ideograph;direction:
ltr;unicode-bidi:embed;vertical-align:baseline;mso-line-break-override:restrictions;
punctuation-wrap:simple">Macleod,
I.; Van Dam, A.: A migration mechanism for transfer of sharks from
ethanol to
aqueous glycerol solutions. Conference Paper. ICOMCC Lisbon 2011.
<br>
</div>
<div
style="language:de;margin-top:0pt;margin-bottom:0pt;margin-left:.31in;
text-indent:-.31in;text-align:justify;text-justify:inter-ideograph;direction:
ltr;unicode-bidi:embed;vertical-align:baseline;mso-line-break-override:restrictions;
punctuation-wrap:simple"><br>
</div>
<div class="moz-cite-prefix">Am 24.06.25 um 16:23 schrieb Esther
Dondorp:<br>
</div>
<blockquote type="cite"
cite="mid:CAGaR2xdaLybZgt6g6UuQ9RQ3R3XncbAsQK=dxL4o=b+fqPT=7A@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">
<div dir="ltr">
<div>Dear all,</div>
<div><br>
</div>
<div>I was following your conversation out of interest and I
am curious why you would not want to add a biocide to
scientific specimens? Is it damaging? I ask this because we
have our largest specimens in a tank in glycerol, because
ethanol was no option (in terms of fire hazard and health
and safety). And we added a lot of thymol to keep mold
out...Also all the 'cleared and stained' specimens in the
collection all have some biocide added to them.</div>
<div><br>
</div>
<div>Thanks!</div>
<div><br>
</div>
<div>
<div dir="ltr" class="gmail_signature"
data-smartmail="gmail_signature">
<div dir="ltr">
<div><span style="font-size:10pt">Esther Dondorp</span></div>
<div><span style="font-size:10pt">Collectiebeheerder
reptielen, amfibieën en vissen</span></div>
<div>
<div style="color:rgb(34,34,34)"><font size="1"><i>absent
on Wednesdays</i></font></div>
<div style="color:rgb(34,34,34)"><font size="1">Monday,
Tuesday, Thursday, Friday</font></div>
</div>
<div><span
style="font-family:arial,helvetica,sans-serif"><a
title="Naturalis-logo"
href="https://naturalis-public-media-assets.s3.eu-central-1.amazonaws.com/Naturalis-mail-signature/logo.png"
rel="noopener" target="_blank"
moz-do-not-send="true"><img
style="float:left;width:160px;height:82px"
src="https://naturalis-public-media-assets.s3.eu-central-1.amazonaws.com/Naturalis-mail-signature/logo.png"
moz-do-not-send="true"></a></span></div>
<p><br>
<br>
<br>
<br>
<br>
<span style="font-size:8pt"><sub> - -</sub></span><br>
<span style="font-size:8pt"><sub><a
href="mailto:esther.dondorp@naturalis.nl"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">esther.dondorp@naturalis.nl</a>
- <a href="https://www.naturalis.nl/"
target="_blank" moz-do-not-send="true">www.naturalis.nl</a></sub></span><br>
<span style="font-size:8pt"><sub>Darwinweg 2, 2333 CR
Leiden</sub></span><br>
<span style="font-size:8pt"><sub>Postbus 9517, 2300 RA
Leiden</sub></span></p>
<div><a href="https://www.naturalis.nl/" target="_blank"
moz-do-not-send="true"><img
src="https://naturalis-public-media-assets.s3.eu-central-1.amazonaws.com/Naturalis-mail-signature/signature-gif.gif"
moz-do-not-send="true"></a></div>
<div> </div>
</div>
</div>
</div>
<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">Op di 24 jun 2025 om 16:12
schreef John E Simmons <<a
href="mailto:simmons.johne@gmail.com" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">simmons.johne@gmail.com</a>>:<br>
</div>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div>
<div
style="font-family:tahoma,sans-serif;font-size:small;color:rgb(0,0,0)"
class="gmail_default">I agree with Dirk--without a
very good seal on the containers, the glycerol will
likely absorb moisture from the air, introducing both
airborne contaminants into the containers and possibly
causing them to overflow (I have had both happen to
containers of specimens in glycerin that were not
properly sealed). </div>
<div
style="font-family:tahoma,sans-serif;font-size:small;color:rgb(0,0,0)"
class="gmail_default"><br>
</div>
<div
style="font-family:tahoma,sans-serif;font-size:small;color:rgb(0,0,0)"
class="gmail_default">Because these specimens do not
have scientific value, you should also consider adding
a biocide to the glycerol such as a few crystals of
thymol or a bit of camphor (as recommended by Simon
Moore).</div>
<div
style="font-family:tahoma,sans-serif;font-size:small;color:rgb(0,0,0)"
class="gmail_default"><br>
</div>
<div
style="font-family:tahoma,sans-serif;font-size:small;color:rgb(0,0,0)"
class="gmail_default">--John</div>
<br clear="all">
</div>
<div>
<div dir="ltr" class="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr"><font
size="2"><span
style="font-family:tahoma,sans-serif">John E. Simmons<br>
Writer and
Museum
Consultant</span></font></div>
<div dir="ltr"><font
size="2"><span
style="font-family:tahoma,sans-serif">Museologica<br>
<i>and</i><br>
Investigador
Asociado,
Departamento
de Ornitologia<br>
Museo de
Historia
Natural,
Universidad
Nacional Mayor
de San Marcos,
Lima</span></font><br>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Tue, Jun 24, 2025 at
9:40 AM Marion BILLOT <<a
href="mailto:Marion.Billot@geneve.ch" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">Marion.Billot@geneve.ch</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<div lang="FR-CH">
<div>
<p class="MsoNormal">Dear colleagues,</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I am currently working on an
exhibition project involving fluid-preserved
specimens, and I am exploring the possibility of
replacing ethanol with glycerol for long-term
display purposes. The main objective is to
reduce fire hazards and mitigate health risks in
display environments (cases that are not
airtight).</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I am preparing to present
this proposal internally. As this practice is
not yet established in my institution and tends
to raise concerns, I would be very grateful for
any feedback from professionals who have
experience using glycerol in this context.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">To clarify:</p>
<ul style="margin-top:0cm" type="disc">
<li style="margin-left:0cm">The specimens are of
strictly pedagogical value, they are not
scientifically rare or culturally significant.</li>
<li style="margin-left:0cm">We aim for long-term
display in semi-sealed cases with limited air
exchange.</li>
<li style="margin-left:0cm">I understand that
transferring specimens from ethanol to
glycerol requires several days of transitional
baths in demineralized water to avoid osmotic
shock and tissue damage. I am considering a
gradual transition: ethanol 70<span
style="font-family:Arial,sans-serif"> </span>%
→ 50<span style="font-family:Arial,sans-serif"> </span>%
→ 30<span style="font-family:Arial,sans-serif"> </span>%
→ 10<span style="font-family:Arial,sans-serif"> </span>%,
followed by glycerol in increasing quart-step
dilutions. I will let it in a minimum of 4
hours for small specimen (5 cm).</li>
</ul>
<p> </p>
<p class="MsoNormal">Have you used glycerol for
display purposes in your institution? If so,
under what conditions, and with what types of
specimens? Any technical advice, protocol
suggestions, or reference materials would be
most appreciated.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Thank you very much in
advance for your insights. They will be very
helpful in supporting a safer and more
sustainable exhibition strategy.</p>
<p class="MsoNormal">Best regards, </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Marion</p>
<p class="MsoNormal"> </p>
</div>
<p><br>
</p>
<table
id="m_1012188531610528675m_4282577591771993297m_6460038527767484809cws"
style="border-collapse:collapse" width="669">
<tbody>
<tr height="8" valign="top">
<td colspan="3"
style="border-style:none;border-color:rgb(0,0,0);border-width:0px;padding:0px"
width="676"><img
src="cid:part1.QAa6J53R.17iE0N8Q@naturhistorische-konservierung.de"
border="0" class=""></td>
</tr>
<tr height="8" valign="top">
<td colspan="3"
style="border-style:none;border-color:rgb(0,0,0);border-width:0px;padding:0px"
width="676"><font color="#4f4f4f"
face="Verdana" size="1"><img
src="cid:part2.utFR2wle.xQy2g09e@naturhistorische-konservierung.de"
border="0" class=""></font></td>
</tr>
<tr height="8" valign="top">
<td
style="border-style:none;border-color:rgb(0,0,0);border-width:0px;padding:0px"
width="253"><font color="#4f4f4f"
face="Verdana" size="1">Marion BILLOT</font><br>
<font color="#4f4f4f" face="Verdana"
size="1">Collaboratrice support
scientifique<br>
Invertébrés<br>
T. +41 22 418 6459</font><br>
<a href="mailto:marion.billot@geneve.ch"
target="_blank" moz-do-not-send="true"><font
color="red" face="Verdana" size="1">marion.billot@geneve.ch</font></a></td>
<td
style="border-style:none;border-color:rgb(0,0,0);border-width:0px;padding:0px"
width="227"><font color="#4f4f4f"
face="Verdana" size="1">Muséum d'histoire
naturelle (MHN)</font><br>
<font color="#4f4f4f" face="Verdana"
size="1">Département de la culture et de
la transition numérique</font><br>
<font color="#4f4f4f" face="Verdana"
size="1">Route de Malagnou 1<br>
1208 Genève</font><br>
<a href="http://www.museum-geneve.ch"
style="text-decoration:none"
target="_blank" moz-do-not-send="true"><font
color="red" face="Verdana" size="1">www.museum-geneve.ch</font></a></td>
<td
style="border-style:none;border-color:rgb(0,0,0);border-width:0px;padding:0px"
width="195"><img
src="cid:part3.B8Xx639k.nPODJ132@naturhistorische-konservierung.de"
border="0" class=""></td>
</tr>
<tr height="8" valign="top">
<td colspan="3"
style="border-style:none;border-color:rgb(0,0,0);border-width:0px;padding:0px"
width="675"><img
src="cid:part1.QAa6J53R.17iE0N8Q@naturhistorische-konservierung.de"
border="0" class=""></td>
</tr>
<tr height="8" valign="top">
<td colspan="3"
style="border-style:none;border-color:rgb(0,0,0);border-width:0px;padding:0px"
width="675"><font color="#4f4f4f"
face="Verdana" size="1">Notre
environnement est fragile, merci de
n'imprimer ce message qu'en cas de
nécessité.</font></td>
</tr>
</tbody>
</table>
<p> </p>
<p><img
src="cid:part4.GuGym3tB.KYEFm746@naturhistorische-konservierung.de"
border="0" class=""></p>
</div>
_______________________________________________<br>
Nhcoll-l mailing list<br>
<a href="mailto:Nhcoll-l@mailman.yale.edu"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">Nhcoll-l@mailman.yale.edu</a><br>
<a
href="https://mailman.yale.edu/mailman/listinfo/nhcoll-l"
rel="noreferrer" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">https://mailman.yale.edu/mailman/listinfo/nhcoll-l</a><br>
<br>
_______________________________________________<br>
NHCOLL-L is brought to you by the Society for the
Preservation of<br>
Natural History Collections (SPNHC), an international
society whose<br>
mission is to improve the preservation, conservation
and management of<br>
natural history collections to ensure their continuing
value to<br>
society. See <a href="http://www.spnhc.org"
rel="noreferrer" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">http://www.spnhc.org</a>
for membership information.<br>
Advertising on NH-COLL-L is inappropriate.<br>
</div>
</blockquote>
</div>
_______________________________________________<br>
Nhcoll-l mailing list<br>
<a href="mailto:Nhcoll-l@mailman.yale.edu" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">Nhcoll-l@mailman.yale.edu</a><br>
<a href="https://mailman.yale.edu/mailman/listinfo/nhcoll-l"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://mailman.yale.edu/mailman/listinfo/nhcoll-l</a><br>
<br>
_______________________________________________<br>
NHCOLL-L is brought to you by the Society for the
Preservation of<br>
Natural History Collections (SPNHC), an international
society whose<br>
mission is to improve the preservation, conservation and
management of<br>
natural history collections to ensure their continuing value
to<br>
society. See <a href="http://www.spnhc.org"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">http://www.spnhc.org</a> for
membership information.<br>
Advertising on NH-COLL-L is inappropriate.<br>
</blockquote>
</div>
</div>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
<pre wrap="" class="moz-quote-pre">_______________________________________________
Nhcoll-l mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Nhcoll-l@mailman.yale.edu">Nhcoll-l@mailman.yale.edu</a>
<a class="moz-txt-link-freetext" href="https://mailman.yale.edu/mailman/listinfo/nhcoll-l">https://mailman.yale.edu/mailman/listinfo/nhcoll-l</a>
_______________________________________________
NHCOLL-L is brought to you by the Society for the Preservation of
Natural History Collections (SPNHC), an international society whose
mission is to improve the preservation, conservation and management of
natural history collections to ensure their continuing value to
society. See <a class="moz-txt-link-freetext" href="http://www.spnhc.org">http://www.spnhc.org</a> for membership information.
Advertising on NH-COLL-L is inappropriate.
</pre>
</blockquote>
<div class="moz-signature">-- <br>
</div>
<div class="moz-signature"><b>Fabian Neisskenwirth</b></div>
<div class="moz-signature">Restaurator/Präparator</div>
<div class="moz-signature"><br>
</div>
<div class="moz-signature">Waterfohrstr. 20</div>
<div class="moz-signature">DE-45139 Essen<br>
<br>
<div class="moz-signature">
<div class="moz-signature">
<div class="moz-signature">
<meta http-equiv="content-type"
content="text/html; charset=UTF-8">
<title></title>
Tel: +49 (0) 1573 2778729 <br>
</div>
<div class="moz-signature"><br>
<div class="moz-signature">
<div class="moz-signature"><a class="moz-txt-link-abbreviated" href="http://www.naturhistorische-konservierung.de">www.naturhistorische-konservierung.de</a><br>
</div>
<div class="moz-signature"><br>
</div>
<img
src="cid:part5.YODs2Y8t.SvueLzIT@naturhistorische-konservierung.de"
moz-do-not-send="false" width="496" height="192"></div>
</div>
</div>
</div>
</div>
</body>
</html>