[Nhcoll-l] Refixing, Ward's solution, and other problems with old specimen

[Dirk Neumann]

Dear Jade,

personally, I would refrain from injecting water-based, acidic 
formaldehyde solution to a specimens sitting in diluted ethanol. 
Especially if the specimen was weakly ethanol "fixed" in the beginning, 
you can't really re-fixate it by exposing it to formalin. The 
formaldehyde can, if at all, only preserve the current condition, but 
not improve it. Second, you might add a lot of osmotic issues, which 
could (further) damage the specimen (not to mention pH issues).

I would try to determine the current concentration of your holding fluid 
and would move the specimen(s) through an rising alcohol ladder 
(normally 20/40/60/75%). Depending on the condition of the specimen, it 
might be good to inject carefully a little bit ethanol inside the body 
cavity of specimens to support this process (not into tissues).

For any further questions centred around fluid collections, I strongly 
recommend John E. Simmons (2014) brilliant and exhaustive "Fluid 
Preservation - a comprehensive reference" (ISBN 9781442229655). 
Comprehensive is an understatement. It's /THE REFERENCE/ combining 
knowledge since the early days of fluid preservation. If "revamping" 
means a taking conservative measures on a larger collection, this book 
might be a very valuable reference during this work.

Regarding the paper: the potential pH shift is correlated with the fluid 
amount inside containers; the same paper might give a strong pH shift in 
a small specimen jar (< 50 ml total volume), while in a 1000 l jar the 
shift might be negligible. In general, also in "normal paper" you may 
have up to 30 different chemicals added during production that are 
trapped inside the paper. A possible alternative would be usage of 
certified archival paper. However, before you shift to another label, 
you should test if your printing method works with the new printing 
medium - not all combinations of "paper" & "printer" produce durable labels.

Hope this helps
Dirk
//

Am 10.09.2015 um 03:32 schrieb Jade Keehn:
> Greetings,
>
> This year, our department is working to revamp a historic fish and 
> herp collection in various states of disrepair. We have been 
> diligently sifting through the curatorial literature to prepare for 
> this process; however, there are a few things we could use some advice 
> on. Hopefully, there are a few knowledgeable wet collection curators 
> who can answer some questions before we begin our assessment and 
> treatment of this valuable collection.
>
> Our first question regards refixing museum specimens. A number of 
> amphibs are in rather "soggy" condition and we are considering 
> injecting them with 10% formalin before  returning them to ethanol 
> solution. This 'refixing' process was mentioned in a 1978 ASIH museum 
> practices document, but we haven't seen it discussed in anything more 
> recent. Are there any potential disadvantages to refixing specimens to 
> improve specimen quality/ longevity?
>
> The herpetological collection is currently labeled using Resistall 
> paper. The literature indicates that this paper type may result in an 
> acidic/damaging pH. Is there another labeling paper that is 
> recommended for use?
>
> A number of specimens have been preserved using Ward's solution. Are 
> there any potential concerns or treatment procedures needed before 
> transferring these specimens into ethanol (75%)? Secondly, is there 
> any reason to worry about the condition of cleared and stained 
> specimens, assuming they are still submerged in fluid?
>
> Thanks in advance for the advice!
>
>
>
> Jade Keehn and James Simmons
> Assistant Museum Curators
> Museum of Natural History
> University of Nevada, Reno
>
>
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-- 
Dirk Neumann

Tel: 089 / 8107-111
Fax: 089 / 8107-300
email: Dirk.Neumann(a)zsm.mwn.de

Postanschrift:

Staatliche Naturwissenschaftliche Sammlungen Bayerns
Zoologische Staatssammlung München
Dirk Neumann, Sektion Ichthyologie / DNA-Labor
Münchhausenstr. 21
81247 München

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---------

Dirk Neumann

Tel: +49-89-8107-111
Fax: +49-89-8107-300
email: Dirk.Neumann(a)zsm.mwn.de

postal address:

Bavarian Natural History Collections
The Bavarian State Collection of Zoology
Dirk Neumann, Section Ichthyology / DNA-Lab
Muenchhausenstr. 21
81247 Munich (Germany)

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