[Nhcoll-l] Restoring a damaged transparent specimen

[Simon Moore]

Hi Claire,

Are you sure that this is lipid that has leached out?  This could be a gradual reaction of an aliphatic compound (glycerol) reacting with residues of M Benzoate and Meth Sal.  The problem with transparencies that are in mixtures of aromatic clearing agents that they too, will gradually interreact over time causing the crystalline growth 

I would need to see a pic of it as it is now and preferably before this reaction occurred, off-list.

With all good wishes, Simon 

Simon Moore MIScT, RSci, FLS, ACR
Conservator of Natural Sciences and Cutlery Historian.

www.natural-history-conservation.com


> On 5 Nov 2025, at 09:18, Claire Smith <claire.smith at reading.ac.uk> wrote:
> 
> Hi everyone, 
> 
>  With apologies for cross-posting, I'm looking for some advice about working with a damaged specimen. 
> 
> It's a newborn monkey that was originally an alizarin transparency, prepared by the Spalteholz technique (https://doi.org/10.1016/s0940-9602(01)80020-0), with our catalogue listing the preservative as "Methyl salicylate 5: benzyl benzoate 4".
> 
> In 2008 it was apparently in poor condition with crystal deposition, and it was transferred into 100% glycerol. 
> 
> Currently, a lipid layer has formed at the top of the fluid, which is also cloudy - presumably also with suspended lipids. 
> The tissue is no longer transparent. 
> 
> My questions are: 
> 
> Is it possible to make the tissues transparent again? (If so, how?!)
> Is it best to keep the specimen in glycerol, but dilute it to a more appropriate concentration? 
> 
> 
> Many thanks,
> Claire
>  *******
> Survey: Fluid Preservation Methods in Biological Collections
> https://app.onlinesurveys.jisc.ac.uk/s/reading/fluid-preservation-methods-in-biological-collections
>  *******
> Claire Smith (she/her), AFHEA 
> Graduate Teaching Assistant: Tuesdays and Wednesdays
> PhD Researcher: Mondays, Thursdays, and Fridays
> 
> Cole Museum of Zoology
> University of Reading
> 
> claire.smith at reading.ac.uk
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