[Nhcoll-l] Alcohol concentration for terrestrial vertebrates

Fri May 7 12:02:29 EDT 2021

Thank you for the citation and for all of this helpful information John!

On Fri, May 7, 2021 at 8:43 AM John E Simmons <simmons.johne at gmail.com>
wrote:

> The reference for the book is:
> Simmons, John E. 2014. *Fluid Preservation: A Comprehensive Reference*.
> Rowman & Littlefield. It is available from Amazon.com, from the publisher,
> and other sellers.
>
> The book includes a discussion (pp 54-56) of botanical fluid preservation
> (thanks to Ann Pinzl for generously sharing with me her as yet unpublished
> research on this subject). Botanists have tended to use some strange
> mixtures, trying to preserve color in their specimens (particularly in
> flowers).
>
> The use of beverage alcohol as a preservative has a long and fascinating
> history. Although most beverage alcohol is below 70%, it usually does a
> fairly good job of preservation (proof is approximately half the alcohol
> concentration, so a 20 proof spirit is about 40% ETOH). I have used
> beverage alcohol to preserve when nothing else was available, and have seen
> a lot of specimens preserved in it. Rum was commonly used because it was
> inexpensive (things such as brandy, which usually has a higher alcohol
> content than rum, actually work better).
>
> Over the history of fluid preservation, there have been many attempts to
> improve the preservative properties of alcohol. In the days before we had
> an easy means to check the concentration, it was common to use alcohol
> after a second distillation, which usually meant around 60-65% (depending
> on the source), so such things as arsenic, mercuric chloride, and other
> chemicals were commonly added to "strengthen" it (they were really just
> making it a more effective biocide, but usually screwing up the specimen in
> the process).
>
> --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, May 7, 2021 at 10:56 AM Mare Nazaire <mnazaire at calbg.org> wrote:
>
>> Thank you Simon and Dirk for your feedback on this.
>>
>> I had actually spoken with the botanist who originally prepared the
>> specimens back in the 60's - he noted that they were preserved in 50% EtOH.
>> He also noted that when he had traveled to other countries for field work
>> and EtOH wasn't available he would use rum! So there could be some other
>> residual components in these fluid preserved specimens!
>>
>> On Fri, May 7, 2021 at 7:18 AM Simon Moore <couteaufin at btinternet.com>
>> wrote:
>>
>>> Dear Mare,
>>>
>>> I have always fixed fresh plant material in Kew mix and then transferred
>>> to Copenhagen mixture which is similar but minus the formalin.  As Dirk has
>>> pointed out, the formulae (proportions) do vary slightly between
>>> institutions, some prefer more glycerine in their mixes but which can make
>>> the specimens rather translucent which is why others prefer a lower
>>> concentration.  There is also the slight problem of osmotic pressure
>>> differential and specimens floating until they equilibrate!
>>> Make sure that the pH of the solutions is a near to 7.0 as possible.
>>>
>>> With all good wishes, Simon
>>>
>>> Simon Moore MIScT, RSci, FLS, ACR
>>> Conservator of Natural Sciences and Cutlery Historian,
>>>
>>> www.natural-history-conservation.com
>>>
>>>
>>>
>>>
>>> On 7 May 2021, at 13:53, Mare Nazaire <mnazaire at calbg.org> wrote:
>>>
>>> This is a very informative and helpful thread - thank you for this!
>>>
>>> I presume that 70% concentration would also be suitable for plant
>>> material preserved in spirits? I ask because I've recently discovered that
>>> some of our collection of fluid preserved plant material is at a
>>> concentration of 50% and I wondered if it is advisable to keep them as is
>>> or change their concentration to 70%. Are there recommendations in John
>>> Simmon's book for preserving plant specimens in alcohol and could you also
>>> provide the citation for this book?
>>>
>>> Thank you,
>>> ~Mare
>>>
>>> On Fri, May 7, 2021 at 12:48 AM Erik Åhlander <Erik.Ahlander at nrm.se>
>>> wrote:
>>> Dear Tonya, John, Simon, Dirk - well all,
>>>
>>>
>>>
>>> Also I agree. Since I will soon retire I want to share some experiences:
>>>
>>> When we started to take care of the collection of wet vertebrates in
>>> Stockholm in 1975 there was no overlap in time (well 1 week) with the
>>> previous staff (the previous curator was employed 1934-1974). So we had to
>>> invent the wheel. The initial ambition was to keep a concentration between
>>> 70 and 80% ethanol. (We also tested the new suggested conservation fluid
>>> Phenoxetol, which after some years showed to be a disaster). To compensate
>>> for evaporation, we tried to stick to 80%. New material was fixed in
>>> formalin for at least a week, washing in water, 20% ethanol for two days or
>>> more, 50% for two days or more, and final storage in 80%. Also we removed
>>> all bad jars from the collection – and a bad jar was a jar that needed
>>> topping. Expedition material was sorted and identified etc after this stage
>>> with the result that many specimens was changed to 80% once more. It took
>>> more than 10 years to realize that 80% was to strong. But also that every
>>> change of alcohol, or topping, resulted in a higher concentration ethanol
>>> since the lowering effect of the alcohol concentration through remnants of
>>> the previus stage fluid inside the specimens was removed. Also the small
>>> amounts of formalin in the specimen was reduced for each change of fluid.
>>> Especially for tiny fish we could find obvious shrinking. Today we are
>>> careful
>>>
>>> 1.       To keep the specimens in 70% (not more, not less)
>>>
>>> 2.       Not to rinse to much in water. Rather remove the formalin from
>>> the surface of the specimen only.
>>>
>>> 3.       Don´t change the fluid if it is not necessary.
>>>
>>> 4.       If you have to remove all fluid, add maybe 80-90% of fresh
>>> (70%) ethanol and the rest used ethanol from another specimen.
>>>
>>> All formalin fixed specimens has a small amount of formalin left - that
>>> is good.
>>>
>>> Some substances in the specimen dissolve in the alcohol (just look at an
>>> alcohol preserved Anguilla…). Every change of alcohol add to the removing
>>> of lipids etc - that is bad.
>>>
>>>
>>>
>>> As far as we know, formalin was used for the first time at the NRM in
>>> 1904, but only occasionally! Still in the 1940s ethanol was commonly used
>>> for fixation in the field. When the museum moved from downtown Stockholm to
>>> north of the city in 1916, the economy for alcohol was reduced due to world
>>> war I (otherwise Sweden was not involved). This led to the invention to use
>>> a diluted formalin solution for the exhibition jars (for specimens fixed in
>>> ethanol!). The research collection continued to be stored in ethanol. Our
>>> collection is old. We estimate that our oldest specimens in ethanol are
>>> from the 1720s (from the Seba collection). Still many specimens from before
>>> 1758 are in remarkable good condition. In some specimens it is even
>>> possible to get small pieces of DNA with ancient DNA technic – but usually
>>> not. This sounds contradicting to some statements above. We don’t know too
>>> much about the preservation history of these specimens, but what we know
>>> might be of general interest. The initial fixation and preservation was in
>>> distilled wine (=“spiritus vini”). We don’t know the concentration, and
>>> probably it was not pure ethanol, but also contained small amount of other
>>> fractions from the wine, more like strong cognac. The Royal collection (of
>>> king Adolf Fredrik with many Linnaean types) was donated to the
>>> Royal Swedish Academy of Sciences in 1801. NRM was founded in 1819, but
>>> immediately in practice fused with the Academy. In 1848 the collections of
>>> the Academy was formally donated to the Museum. From the 1740s to 1970 this
>>> collection of  vertebrates in alcohol was moved four times. Jars and fluid
>>> was probably changed twice. But most of the time the collection was stored
>>> cool and dark. Glasses and fluids was expensive so the ratio: specimen
>>> volume / conservation fluid volume was high up to 1900.  From 1801-1898 the
>>> major part seems to have been almost untouched, except that the whole
>>> collection was moved 1500 meters in 1829.
>>>
>>>
>>>
>>> I was once asked how long a specimen could be stored in alcohol. With
>>> the reservation that our old specimens will be stored like today, no sudden
>>> disasters etc (and no climate change), I decided that to 2220 = 500 years
>>> would be possible, maybe 1000 years.
>>>
>>>
>>>
>>>
>>>
>>> Erik Åhlander
>>>
>>> vertebrate zoology and museum history
>>>
>>>
>>>
>>> ZOO
>>>
>>> Swedish Museum of Natural History
>>>
>>> PO Box 50007
>>>
>>> SE-10405 Stockholm
>>>
>>> Sweden
>>>
>>> +46 0 8 5195 4118
>>>
>>> +46 0 70 225 2716
>>>
>>> erik.ahlander at nrm.se
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> Från: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> För Dirk Neumann
>>> Skickat: den 7 maj 2021 08:36
>>> Till: nhcoll-l at mailman.yale.edu
>>> Ämne: Re: [Nhcoll-l] Alcohol concentration for terrestrial vertebrates
>>>
>>>
>>>
>>> Hi Tonya (and John and Simon ;-)
>>>
>>>
>>>
>>> concur with John and Simon, specimens should be kept in 70%; Simon
>>> pointed to the diluting effects and the image below nicely illustrates
>>> this: even if you use more steps for transferring specimens (0/20/40/60/80
>>> vs. 20/30/50/70), tissues are still soaked with 60% or less high
>>> concentrated EtOH.
>>>
>>>
>>>
>>> Depending on size, body mass and number of specimens (i.e. amount of
>>> tissue in the jar), the effect can be considerable (see "staining" in the
>>> images below; in the left one, body fluids released from these tall
>>> whitefish are indicated by the reddish haemoglobin stain at the bottom of
>>> the jar, the overall greenish colour in the right comes from chlorophyll
>>> released from the guts of these herbivorous distichodus fish).
>>>
>>>
>>>
>>> I do the initial filling usually with 73-75% EtOH to reach 70%; aside
>>> from vertebrates high EtOH concentrations can be an issue in malaise traps
>>> because there the specimens usually are collected over several days or
>>> weeks in 96-80% EtOH. As Simon pointed out this quickly dehydrates
>>> specimens and weakens the joints holding all the antennae, appendices,
>>> bristles of invertebrates. Another issue is that in unsorted malaise trap
>>> samples there often is a thick deposit of specimens at the bottom of the
>>> container. Because the diluted less high concentrated ethanol is heavier,
>>> it layers at the bottom of the jar (cf. whitefish jar). Inside malaise trap
>>> containers, this diluted EtOH may get trapped in the thick specimen deposit.
>>>
>>>
>>>
>>> Usually, I leave jars for few day to see if there are any unwanted
>>> effects before moving them into the collection.
>>>
>>>
>>>
>>> Hope this is useful, with best wishes
>>>
>>> Dirk
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> <image001.png>
>>>
>>>
>>>
>>> Am 07.05.2021 um 00:17 schrieb Simon Moore:
>>>
>>> Thanks John and Tonya,
>>>
>>>
>>>
>>> What John says is true about the staging of alcohols and the final
>>> concentrations.  80% was what I was advised at the NHM in London when I
>>> worked there and by the time larger terrestrial vertebrates ‘end up’ in
>>> 80%, you will often find that with the mix of lower grade alcohols from the
>>> staging process, once things have settled down / equilibrated, then the net
>>> result is around 70% anyway.  Higher grade alcohols  can lead to
>>> embrittlement of certain tissues as well as evaporation issues.
>>>
>>>
>>>
>>> I have also found the staging process necessary for the more fragile
>>> specimens as they undergo changes in Osmotic pressure during this process
>>> which can cause syneresis or shrinkage in softer tissues.
>>>
>>>
>>>
>>> With all good wishes, Simon
>>>
>>> Simon Moore MIScT, RSci, FLS, ACR
>>> Conservator of Natural Sciences and Cutlery Historian,
>>>
>>> www.natural-history-conservation.com
>>>
>>>
>>> <image002.jpg>
>>>
>>>
>>>
>>>
>>> On 6 May 2021, at 22:50, John E Simmons <simmons.johne at gmail.com> wrote:
>>>
>>> Tonya,
>>> Thank you for your kind words about my book. The recommendation for
>>> staging up to 80% concentration was by made by my friend Simon Moore, who I
>>> cited in that sentence. In general, I do not recommend using 80% ETOH as a
>>> preservative for terrestrial vertebrates, but rather 70%. Preservation is
>>> alcohol is a trade-off between dehydration of the specimens and providing
>>> them suitable protection against biological deterioration. At 70%, ETOH is
>>> a very good biocide; below that, not so good, and above 70%, too strong for
>>> most specimens (note that there are some instances in which 80% might be
>>> preferred).
>>>
>>> I do not recommend using stronger alcohol as a hedge against
>>> evaporation--that leads to uneven concentrations of preservatives and can
>>> be a real mess to work with in a collection.
>>>
>>> For how-to instructions on preserving, transferring specimens, and
>>> managing a fluid preserved collection, you might want to check
>>> Herpetological Collecting and Collections Management (3rd edition, 2015).
>>> The instructions for preserving and managing fluid preserved animals will
>>> work for most other specimens as well as for reptiles and amphibians.
>>>
>>> Hope this helps,
>>> --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 Thu, May 6, 2021 at 4:05 PM Haff, Tonya (NCMI, Crace)
>>> <Tonya.Haff at csiro.au> wrote:
>>> Hello all,
>>>
>>> I am enjoying reading John Simmon's fantastic book on fluid
>>> preservation. In it I read one suggestion for stepping specimens up out of
>>> formalin fixative into preservation alcohol as follows: from 20% ETOH to
>>> 40% to 60% and finally to 80%. We typically place our specimens in 70%
>>> ETOH, and I know higher concentrations can cause some problems with
>>> specimen dehydration. All our specimens are terrestrial vertebrates. I
>>> presume the final 80% provides a buffer against ETOH evaporation or
>>> leaching of water from the specimen into the fluid in the jar, to ensure
>>> that the alcohol concentration in the preservation fluid stays sufficiently
>>> high? But to me this is not quite clear. I wonder if any of you have
>>> thoughts on this, or if you would be willing to share how you step your
>>> specimens up in ETOH?
>>>
>>> Thank you!
>>>
>>> Tonya
>>>
>>>
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>>> 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 http://www.spnhc.org for membership information.
>>> Advertising on NH-COLL-L is inappropriate.
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>>> --
>>>
>>> <image004.png>
>>>
>>>
>>> Dirk Neumann
>>>
>>> Tel: 089 / 8107-111
>>> Fax: 089 / 8107-300
>>> neumann(a)snsb.de
>>>
>>> Postanschrift:
>>>
>>> Staatliche Naturwissenschaftliche Sammlungen Bayerns
>>> Zoologische Staatssammlung München
>>> Dirk Neumann, Sektion Ichthyologie / DNA-Storage
>>> Münchhausenstr. 21
>>> 81247 München
>>>
>>> Besuchen Sie unsere Sammlung:
>>> http://www.zsm.mwn.de/sektion/ichthyologie-home/
>>>
>>> ---------
>>>
>>> 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)
>>>
>>> Visit our section at:
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>>>
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>>>
>>> _______________________________________________
>>> 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 http://www.spnhc.org for membership information.
>>> Advertising on NH-COLL-L is inappropriate.
>>>
>>>
>>> --
>>> Mare Nazaire, Ph.D.
>>> Administrative Curator, Herbarium [RSA-POM]
>>> California Botanic Garden
>>> Research Assistant Professor, Claremont Graduate University
>>> 1500 North College Avenue
>>> Claremont, California 91711
>>> 909.625.8767 ext. 268
>>> _______________________________________________
>>> Nhcoll-l mailing list
>>> Nhcoll-l at mailman.yale.edu
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>>>
>>> _______________________________________________
>>> 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 http://www.spnhc.org for membership information.
>>> Advertising on NH-COLL-L is inappropriate.
>>>
>>>
>>>
>>
>> --
>> Mare Nazaire, Ph.D.
>> Administrative Curator, Herbarium [RSA-POM]
>> California Botanic Garden
>> Research Assistant Professor, Claremont Graduate University
>> 1500 North College Avenue
>> Claremont, California 91711
>> 909.625.8767 ext. 268
>> _______________________________________________
>> Nhcoll-l mailing list
>> Nhcoll-l at mailman.yale.edu
>> https://mailman.yale.edu/mailman/listinfo/nhcoll-l
>>
>> _______________________________________________
>> 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 http://www.spnhc.org for membership information.
>> Advertising on NH-COLL-L is inappropriate.
>>
>

-- 
Mare Nazaire, Ph.D.
Administrative Curator, Herbarium [RSA-POM]
California Botanic Garden
Research Assistant Professor, Claremont Graduate University
1500 North College Avenue
Claremont, California 91711
909.625.8767 ext. 268
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