Mike Patterson wrote:

>You should be able to get denatured anywhere alcohol you can find paint
>cleaning
>supplies. A handy substitute is radiator fluid (ethylene glycol). There was
>a time when you could get formalin (formaldyhyde) at the drugstore which is
>the chemical of choice for initial preparation of specimens. It reacts with
>proteins and hardens them. Alcohol does not. National marine fisheries
>folks collect specimens in formalin and transfer to alcohol if they plan
>on lots of close dissection work. Formalin has been identified as a
>cancer causing agent.

But I think that many invertebrates preserve better in alcohol than in
formalin. Vertebrates of all kinds (including BIRDS) are always preserved
in formalin to harden them best, then changed to 70% ethanol for final
storage (just because formalin is very unpleasant to work with, besides
being carcinogenic). Now that we realize formalin really messes up DNA,
specimens intended for molecular-systematics studies are being preserved
originally in alcohol.

Insects are preserved originally in alcohol (70-80% ethanol or
isopropanol), as are at least small mollusks (I spent a summer collecting
and preserving land and freshwater snails), and I thought that was true for
at least some other marine groups. Do you have details on that, Mike?
Others, I think primarily soft-bodied critters such as coelenterates, must
be kept in formalin because alcohol dehydrates them. There is a great book
by Jens Knudsen, formerly of Pacific Lutheran University, on the collection
and preservation of biological materials. Long out of print,
unfortunately.

Good to have you back on tweeters, Mike.

Dennis Paulson, Director phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416