Hello Philip
I made those very same points a few months ago. I was pummeled and nearly 
declared insane. You and I know what vitreous means because of applications in 
electron microscopy.  Super-rapid freezing is for us the only way.
Oddly though, freezing under Cryo Jane's rather slow conditions, you can avoid 
large crystals and freezing damage that obvious under the OM. Its not truly 
vitreous and would not do for EM, but it works for histologists and they like 
the term vitreous.
Let them be.
Cheers
Jim Darley
ProSciTech                 Microscopy PLUS
PO Box 111, Thuringowa  QLD  4817  Australia
Ph +61 7 4774 0370  Fax:+61 7 4789 2313  service@proscitech.com
Great microscopy catalogue, 500 Links, MSDS, User Notes
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On Thursday, April 06, 2000 4:17 AM, Philip Oshel 
[SMTP:peoshel@facstaff.wisc.edu] wrote:
> I have to take issue with a piece of this post. The description of
> what the "Gentle Jane" is doing in terms of freezing cannot be
> correct. In order to form vitreous ice, or the microcrystalline ice
> that many folks call "vitreous", freezing rates must exceed 10,000
> deg. C per second, and even at that rate, only the outmost 500
> microns (at best) of a sample will be "vitreous". This is of a very
> small sample of maybe 1 cubic millimeter or so. Larger than that, and
> the sample retains enough heat that the
> 10,000 deg/sec freezing rate will not be obtained as deeply as 500
> microns. Also, this is only possible in a high-pressure freezer where
> the sample is frozen at around 2100 barrs pressure. Less than this
> and only 100 or so microns of sample will have "vitreous" ice. The
> increased pressure coupled with the rapid freezing forces the ice to
> take on a cubic crystal structure instead of its more familiar
> hexagonal structure, or the pressure prevents formation of a
> crystalline lattice at all (the major reason for this is that the
> hexagonal crystal structure takes up more volume than the cubic or
> "vitreous" phases, and the high pressure prevents this volume
> increase).
>
> Freezing by simple contact for 8-10 seconds at standard pressure at
> any temperature cannot result in vitreous ice or even cubic ice. It
> may very well form smaller or much smaller than normal ice crystals,
> and the damage caused by these crystals may well be below the
> resolution of the light microscope (as normally used, anyway), but
> the sample will be full of nice, hexagonal ice. So, the sample will
> have all the dehydration and mechanical damage caused by the
> formation of this ice, just not at a light microscopic level (one
> hopes).
>
> Phil
> (Grunt running the High-Pressure Freezer and cryo-FESEM.)
>
> >Hi Histonetters,
> >
> >All the  "Janes" are confusing!  Clarification!
> >
> >The Gentle Jane (Stand Alone Gentle Jane) is a snap freezing system. A
> >weighty heat extractor is chilled (preferable in liquid nitrogen) and then
> >it is hung on the device. It drops at a controlled rate and gently contacts
> >the tissue and CryoGel or other embedding medium. The block is frozen in
> >8-10 seconds. The temperature of the heat extractor,-196deg. C, and the
> >thermal exchange derived from its highly polished chrome finish, produces
> >"amorphous" ice rather than "crystalline" ice. minimizing ice crystal
> >artifact. The morphology of the tissue is preserved!
> >
> >The CryoJane Tape-Transfer  system is installed in the cryostat. The section
> >is cut onto a cold tape and transferred to a cold slide inside the cryostat.
> >The section stays frozen until the section is fixed, freeze-substituted or
> >air-dried. This process produces paraffin-quality frozens that are thin,
> >flat and intact. Yes, and you cut fat, bone etc.with little sweat!
> >
> >Bernice
> >schiller@instrumedics.com
>
> }}}}}}}}}}}}}}}}}{{{{{{{{{{{{{{{{{
> Philip Oshel
> Supervisor, AMFSC and BBPIC
> Dept. of Animal Health and Biomedical Sciences
> University of Wisconsin
> 1656 Linden Drive
> Madison,  WI  53706-1581
> voice: (608) 263-4162
> fax: (608) 262-7420 (dept. fax)