Recrystallizing naphthalene on natural history specimens

Erin Chapman <erchapman75 [at] yahoo__com__au> writes

>My minor thesis topic is the preparation, storage, and care of the
>Queensland Museum's Bat Collection. The bats in the Queensland
>Museum collection were collected to be used for research purposes,
>and as such, are not used for display within the museum. A large
>number of the bats exhibit a white crystalline powder on the outer
>surface of their skin, particularly around the legs and wings. The
>substance does not seem to be deleterious to the specimens.
>Preliminary examination and research into this problem indicates
>that the substance is more likely to be a re-crystallisation of
>naphthalene.

I have never come across naphthalene as a substance laid down as a
re-crystallisation on skins before.  You may have already 'been
there' but the most usual are arsenic salts from arsenical soap,
used as a skin preservative before 1960s, also mercuric chloride.
Other possibles are borax or other borates, tri-basic sodium
phosphate (used as a skin rehydrator).  The problem is that
preservatives and fumigants can accumulate over time and give a
rather mixed result when the salts are analysed.

Simon Moore, MIScT, FLS, ACR,
Senior Conservator of Natural Sciences
Hampshire County Council
Recreation and Heritage Department
Museums and Archives Service
Chilcomb House
Chilcomb Lane
Winchester SO23 8RD, UK
+44 1962 826737


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                  Conservation DistList Instance 20:31
                Distributed: Saturday, December 9, 2006
                       Message Id: cdl-20-31-007
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