[NHCOLL-L:4541] RE: Question about Wet Collection

[Moore, Simon]

 Hi Ashley,

As has been suggested, you need some new jars first.  Andy has mentioned the Alcomon beads - these are fine to monitor dilution rates but will only work as fluid specific-gravity testers.  If you make up some solutions of set concentrations of alcohols - 20%, 40% &c and see how the 2 beads, which are of different density plastics, behave in these concentrations - they will float, sink, hang half-way.  If your specimens are not too fragile you could put all of those in low-level (30%) alcohol and then take them up a dehydrating ladder of alcohols to preserving strength (70-80%).

Assuming that none of the specimens is actually dry, then you shouldn't need to re-fix in formalin, so you won't need to make the distinction, except that delicate and translucent zoological specimens require 5% formalin preservation unless being used for DNA analysis.  

To distinguish between alcohol and formalin you will need to find some Feulgen solution, from your histology department if you have one, (aka Schiff reagent), pipette some onto dry filter paper, leave to dry and then cut up the paper into strips and store in a dark and dry container.  These strips will distinguish an aldehyde presence which releases the hidden dye (basic fuchsin) so you will get an immediate bright magenta reaction for a formalin presence. A dull mauve or a very slow release of the magenta dye is a negative reaction.

Hope that this will help.


With all good wishes, 
Simon Moore, MIScT, FLS, ACR,
Senior Conservator of Natural Sciences. 
Hampshire County Council,
Department of Culture, Communities and Rural Affairs,
Museums & Archives Service,
Chilcomb House, Chilcomb Lane,
Winchester SO23 8RD. UK.
Internal  8 327 6737
01962 826737
http://www.hants.gov.uk/museum/biology 



-----Original Message-----
From: owner-nhcoll-l at lists.yale.edu [mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Bentley, Andrew Charles
Sent: 23 September 2009 20:00
To: AshleyH at cctexas.com; NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:4539] RE: Question about Wet Collection

Hi Ashley

Yes, your first course of action is to get rid of those Bakelite lids - they are terrible.  There are numerous suppliers of good alcohol resistant lids if you have not found one yet.  We use KOLS Containers and I would be happy to give you there details or to send you samples of various sizes if need be.  They should fit your existing jars.

As for the concentration problem, short of purchasing expensive equipment to determine actually concentration you could try the bead system developed by Alcomon.  Two plastic beads of different densities are placed in the alcohol and then float at different levels to give an indication of approximate concentration.  You can then adjust accordingly. http://www.alcomon.com.  I have some samples given to me the developer Dries van Dam if you would like to try them - or you may be able to get a sample from Dries.

In cases where there is very little fluid left or the fluid is badly discolored it may be wise to replace all fluid instead of trying to "make it up" to the correct concentration.

Hope that helps.  Let me know if you have any further questions.

Andy

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Andy Bentley
Ichthyology Collection Manager/Specify Usability Lead University of Kansas Natural History Museum & Biodiversity Research Center Dyche Hall
1345 Jayhawk Boulevard
Lawrence, KS, 66045-7561
USA

Tel: (785) 864-3863
Fax: (785) 864-5335
Email: ABentley at ku.edu       
                                                
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-----Original Message-----
From: owner-nhcoll-l at lists.yale.edu [mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Ashley Henderson
Sent: Wednesday, September 23, 2009 12:58 PM
To: NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:4538] Question about Wet Collection

Hi Everyone,

I am looking for some advice about wet specimens.  I recently became the Collection Manager at a museum with around 1,000 wet specimens.  My experience with them is very limited.  I have read many articles regarding their preservation, but I still have some how-to questions and am seeking some advice.  The wet collection is mostly herpetology and marine biology with some entomology.  They are in glass jars ranging in size from a half gallon to small vials.  Most jars have plastic Bakelite lids, which I have read allow for a great amount of evaporation.  Some of the specimens are 30 to 40 years old and have been topped off countless times.  Some of the jars have not been topped off recently and are half empty.  So, I am dealing with a wet collection for which I have no idea what the ethanol concentration is from jar to jar.  I would like to work through the collection and bring each up to 70% ethanol.  From my research, I understand that it is best to avoid completely changing out the preservative.  What is the best way to test the preservative in the jars so that I can then add the appropriate amount of ethanol to establish a  70% level?  I have researched using hydrometers.  However, many of the specimens in small jars do not have enough preservative to remove a sample for testing.  What other methods are there and what would be the best process for testing each of the specimens?  Or is it even necessary?  Any advice would be greatly appreciated.

Thanks,



Ashley Henderson

Collection Manager
Corpus Christi Museum of Science and History www.ccmuseum.com
(361) 826-4659