Hello all,
  I am attempting to do some histological work on leeches.  Cross
sections are needed so the leech has to be standing on end in the
embedding mold, which is about 3/4" deep.  I've never had a problem
before, but for some reason there are large air bubbles forming in
the paraffin.  Sometimes breaking through to the top otherwise just
below the top surface.  They are rather large and I often have to
melt the block and embed again because the leech will be sticking
into the air bubble.  Has anyone ever run across this problem?  Does
anyone know any possible solutions?  I fill the mold as much as
possible without overflowing and there has been no changes in brand
of paraffin or temperatures of the embedding center.  I have also
tried not putting the mold on the cold plate afterward and letting it
cool at room temperature, which has no effect.
Thank you in advance,
  Julianne Rowehl
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Julianne Rowehl
Virginia Institute of Marine Science
P.O. Box 1346
Gloucester Point, VA 23062
(804) 684-7459
Shipping Address: Rt. 1208 Greate Road