[NHCOLL-L:5139] RE: white crystals appearing on specimens in fluid, any i...

[Couteaufin at aol.com]

Heather,
 
I have observed this before on specimens prepared by Fric (Prague) et al.  
where little white waxy blobs form on the edge of the vials covered with 
netting  - I presume that yours are similar.
Chemically these should dissolve in alcohol but if the preservative  
contains enough aqueous-based reagents then the precipitation/coagulation is  
possible.  Could well be cholesterol.  I am still surprised however,  that it 
forms on top of the tubes rather than the specimens themselves.
 
Hope that this ramble is useful in some way.
 
With all good  wishes, Simon

Simon Moore MIScT, FLS, ACR,
Conservator of Natural  Sciences,
20 Newbury Street,
Whitchurch RG28 7DN.
_www.natural-history-conservation.com_ 
(http://www.natural-history-conservation.com/)  
_www.pocket-fruit-knives.info_ (http://www.pocket-fruit-knives.info/)  

_http://uk.linkedin.com/in/naturalsciencespecimenconserve_ 
(http://uk.linkedin.com/in/naturalsciencespecimenconserve)   


In a message dated 16/12/2010 22:20:54 GMT Standard Time,  
JPRICE at mus-nature.ca writes:

Heather

I had similar stuff in a jar of tapeworms, although  in this case it was 
white pearly flakes. I had our mineralogy guys run it  under the x-ray 
chromatograph.  They tell me it's cholesterol, likely  dissolved out of the tissues 
and then precipitated.

But dammit Jim, I'm  a collection manager, not a chemist!
Judith

Judith C.  Price
Secretary, Society for the Preservation of Natural History  Collections
Assistant Collections Manager, Invertebrates / Gestionnaire  adjointe des 
collections invertébrés
Canadian Museum of Nature / Musée  canadien de la Nature
PO Box 3443 Station D / CP 3443 Succ  <<D>>
Ottawa, Ontario K1P 6P4 CANADA
Tel.613.566.4263 /  Fax.613.364.4027
jprice at mus-nature.ca
@nature_jcp
www.nature.ca /  www.spnhc.org



-----Original Message-----
From:  owner-nhcoll-l at lists.yale.edu [mailto:owner-nhcoll-l at lists.yale.edu] 
On Behalf  Of Heather Campbell
Sent: Thursday, December 16, 2010 3:21 PM
To:  NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:5137] white crystals appearing  on specimens in fluid, 
any ideas?


Hello all,

While rehousing  the bee wet collection I have noticed that some vials
contain specimens  that have white material growing (?) on them.  Here are
a few details  that may be important when considering a diagnosis:
1. Only vials  containing larvae (maybe pupae) are affected
2. Different species and  different years (but always older than 5yrs) and
different locals
3.  Preservative used: Kahle's sol
acetic acid (glacial) 10%
formalin (37%)        10%
water     25%
Ethanol  (75%)         55%
4. Easily scraped away and has a  plaque-like resemblance
5. no visible damage done to specimen (naked  eye)

I have pictures but am unable to send due to limits on message  size.  I
will be happy to send these along to anyone who is  interested.

Thank you

Heather M. Campbell
Bee Curatorial  Assistant
Division of Invertebrate Zoology
American Museum of Natural  History
Central Park West @ 79th st.
New York, NY  10024-5192
212-496-3447


Heather M. Campbell
Bee Curatorial  Assistant
Division of Invertebrate Zoology
American Museum of Natural  History
Central Park West @ 79th st.
New York, NY  10024-5192
212-496-3447
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