Re: [Histonet] canada balsam


We ring our aqueous mounting media with finger nail polish. Aqueous mounting
media does not really dry out and harden, and keeps oozing out from under
the coverslip and the coverslip keeps moving, so was always making a mess of
the slide, especially for filing. The aqueous mounting media will eventually
dry out, but then all you are left with is dried sugar under the
coverslip(terrible refractive index at that point (tongue-in-cheek)). The
finger nail polish kept the aq. mounting media from oozing and slowed down
the drying out of the aq. mounting media to sugar.

On the other hand, Canadian balsam is basically pine tree sap diluted with
xylene or toluene. Stays runny and sticky for a long time. I remember
placing the slides in the 60 degree C. oven for 1 week after coverslipping,
to solidify the mounting media enough for us to file the slides. I suppose
it is possible that someone could have ringed the coverslip with finger nail
polish after coverslipping, just to prevent the slight oozing and the
coverslip from moving around. I had never thought to do it, but then we were
coverslipping 300 slides a day in the lab at the time, and ringing is not
time efficient for that quantity.

Thank goodness for the modern day mounting medias with their faster drying
times (30 minutes to non-stickiness) and their non-acidic pH so the stains
don't fade with time (which is why we  have to restain old slides of H&E
that were originally mounted with Canadian balsam).

Peggy A. Wenk, HTL(ASCP)SLS
William Beaumont Hospital
Royal Oak, MI 48073

----- Original Message -----
From: "Gudrun Lang" 
To: "Histonetliste" 
Sent: Saturday, August 14, 2004 11:12 AM
Subject: [Histonet] canada balsam

Hi all,
A little question by interest. Was it canada balsam where you have to margin
the coverslip with paraffin or nail polish to avoid drying out?
Or was this only necessary with aqueous medias?


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