insecticides used in herbaria

Lyn.Craven at CSIRO.AU Lyn.Craven at CSIRO.AU
Thu Feb 3 09:24:00 CST 2005

This is an interesting posting.   Younger staff, in smaller institutions
in particular, are missing out on accessing the "corporate memory", for
want of another term.

The black, powdery material may indeed be a nasty, toxic substance
(interesting how the first responses alluded to mercuric chloride, still
in use by some tropical institutes interested in preserving their
specimens, but that's another story).

It might also be coal dust.  In the 1800s, the prevalence of coal fires
for household (and herbaria?) heating must have led to an enomous amount
of particulate matter in the air.  Look at specimens from some of the
older European herbaria;  one sometimes has to use a damp cloth to wipe
off the dust before annotation slips will adhere.

Regards,    Lyn

-----Original Message-----
From: Taxacom Discussion List [mailto:TAXACOM at LISTSERV.NHM.KU.EDU] On
Behalf Of Gayle
Sent: Thursday, February 03, 2005 3:50 AM
Subject: [TAXACOM] insecticides used in herbaria

Dear Taxacom members,

I have been going through old herbarium specimens (circa 1800's)
borrowed from some prominent old herbaria.  Some of the specimens
(algal) are coated with a black powdery substance and the paper is
browned and disintegrating.  When I first pulled the specimens from
their cabinets (some that hadn't been opened in many years), the toxic
smell in the cabinets was pretty overwhelming.  Now that the specimens
have been in boxes outside the cabinets, they no longer smell but some
still have this powdery substance on them.  

My question is:  What insecticides have been used by herbaria in the
past?  Can people be affected by these toxins by smelling or touching
them?  Do these toxins break down in time so that older herbarium
specimens are safe?  If they are toxic, are there antidotes or safety
measures for looking at these specimens?


Gayle Hansen
Hatfield Marine Science Center
Newport, Oregon

gayle.hansen at

More information about the Taxacom mailing list