[Nhcoll-l] Transferring a worm to new fixative

Thu Mar 26 05:55:44 EDT 2026

Dear all,

Oligochaeta are often preserved in a mixture of formalin and alcohol.
The mixing ratio can vary (depending on the preparer’s
personal experience or the advice of their teachers).
Typically, a mixture of 90% alcohol and 35% formalin is used in a ratio
of 9:1.

If the ratio of the new solution does not match the original, osmotic
differences arise, leading to the problem described here.

btw: Fabian is absolutely right. Although the old methods can largely be
ruled out here, there is often something of an alchemy
involved in the preservation of ‘worms’. Particularly with Oligochaeta,
Schaudinn’s fixing mixture was often used (1 part
sublimate solution / 1 part 95% alcohol).

Fritz Schaudinn first published the formula in 1895, and later published
it frequently in various modifications. This toxic agent
is still in use in microscopy today,

All the best,
Joachim

--  
Joachim Haendel

Center of Natural Science Collections
of the Martin Luther University (ZNS)
- Zoological Collection -

Domplatz 4
D-06099 Halle (Saale)
Germany

Phone:  +49 345 - 55 26 447
Email: joachim.haendel at zns.uni-halle.de

>>> Am 26.03.2026 um 07:34, Fabian Neisskenwirth
<info at naturhistorische-konservierung.de> schrieb:

Dear all,

just as a safety advice. Please do not smell preservation fluids. This
practice is very dangerous and unprofessional. There are
many simple methods to test physical properties and if there is an
aldehyde content in the fluid.

The density alone of the fluid can give already a lot of information.

All the best,

Am 25.03.26 um 22:38 schrieb William Poly:
> Hi Nate,
>  
> AFA (alcohol, formalin, acetic acid) is another possible solution as
it is used for worms, and the combination of odors could
> make it difficult to identify by smell.
>  
> Bill
>  
> 
> On Wed, Mar 25, 2026 at 12:57 PM Shoobs, Nate <shoobs.1 at osu.edu
[shoobs.1 at osu.edu]> wrote:
> > Hey all,
> > We have a display specimen of a Giant Australian earth worm
(Megalascides) with no data in our collection. It's in nice
> > condition, but the fluid it's preserved in is quite dark orange
(presumeably colors leeched from the animal) and thus it makes
> > the specimen hard to see and appreciate.
> >  
> > I want to transfer it to fresh fluid so it's easier to examine, but
I can't figure out what it's preserved in. I initially
> > thought it was in 10% formalin, but test-dipping a portion of the
animal in a fresh jar of 10% formalin caused a pretty
> > immediate visible reaction (skin started peeling). The preservative
is definitely not ethanol. It has an acrid odor like
> > formalin. I don't have Schiff's reagent on hand. The specimen was
acquired in the mid 60s early 70s, so I think it rules out
> > many of the more obscure Victorian fixatives.
> >  
> > Any suggestions on a protocol to safely transfer it to a fixative
that is less opaque (fresh formalin or ethanol)? The primary
> > purpose of the transfer is for display and teaching, as the specimen
is uncatalogued and has no data other than the ID, so the
> > only thing that matters in this case is making sure it's not ruined
aesthetically. (And of course, making sure I can figure
> > out what the old preservative is to safely dispose of it).
> >  
> > -Nate
> > -
> > Nathaniel F. Shoobs, Curator of Mollusks
> > 
> > College of Arts & Sciences Dept. of Evolution, Ecology, and
Organismal Biology, The Ohio State University
> > Museum of Biological Diversity
> > 1315 Kinnear Rd, Columbus, OH 43212
> > 614-688-1342 (Office)
> > mbd.osu.edu
> >
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--
Fabian Neisskenwirth
Restaurator/Präparator

Waterfohrstr. 20
DE-45139 Essen

Tel: +49 (0) 1573 2778729

www.naturhistorische-konservierung.de
[http://www.naturhistorische-konservierung.de]

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