[NHCOLL-L:871] Re: Rehydrating fish specimens

[SIMMONS]

I have not had experience rehydrating fish, but have tried various
reptiles and amphibians.  After investigating the various methods in the
literature and trying a good number of them, I have reached the conclusion
that most rehydation attempts bring only disappointment.  When a curator
brings me in a shriveled up little treasure now and begs to have it
restored to its former splendor, I always ask why they want it rehydrated.
In most instances, we are better off to leave the specimen dried up than
to shorten its shelf life or completely destroy it in a rehydration
attempt.

I have read the article that recommends Drano.  I am baffled by why anyone
would attempt such a thing.  We already know that enzyme detergents used
to prepare skeletons create "time bombs" in that the bones deteriorate far
faster than those prepared by other means (Shelton, S.Y. and J.S. Buckley.
1990.  Observations on enzyme preparation effects on skeletal material.
Colletion Forum 9(2):76-81).  If you stop to ponder what Drano is designed
to do, you will be hard pressed to find a reason to let it anywhere near
your collection, much less use it to rehydrate specimens.

The oral tradition of museums records the use of 30% ammonia solutions,
soapy water, 2:1 hydrogen peroxide and water, etc.  None work very well.

A brief bibliography for you (I do not endorse any of these techniques):

Cleave, H.J. and J.A. Ross.  1947.  A method for reclaiming zoological
specimens.  Science 105:318 [0.25-0.50% trisodium phosphate]
Marhue, L.  1983.  Techniques to restore dried-up invertebrate specimens.
Syllogeus 44:175-177

Vogt, K.D.  1991.  Reconstituting dehydrated museum specimens.  Curator
34:125-131 [pre-soak in acetic acid, surfactant, re-fixation]

Vogt, K.D.  1998.  The reconstitution of dehydrated museum specimens II.
The Biology Curator 13:6 [This is the infamous Drano/Liquid Plumber paper]

Sorry to sound so negative, but the long-term effects of rehydration are
very bad, so you must carefully consider what you need to use the specimen
for.  I would recommend not rehydrating it unless you needed it rehydrated
immediately.

John Simmons
Natural History Museum
University of Kansas

> We are currently investigating methods of rehydrating fish specimens and
> would appreciate hearing from anyone who has had experience in this
> area. In the past the museum has used a solution of tri-sodium
> orthophosphate, but recently has become aware of a method using
> enzymatic drano built up remover (an American product). Does anyone have
> any information or comments about this alternative or about rehydration
> of specimens in general?
> 
> Sue Valis
> Conservator
> Australian Museum 
> 6 College Street
> Sydney NSW 2010
> Australia
> 
> tel: +61 2 9320 6207
> fax: +61 2 9320 6070
>