X-Message-Number: 3600
Subject: SCI.CRYONICS: Flash Freezing
Date: Thu, 05 Jan 1995 08:38:22 -0500
From: "Perry E. Metzger" <>


From: Brian Wowk <>

>         Although I generally agree with Perry Metzger's responses to
> Jan Coetzee, I must take issue with one minor but significant point.
> There actually is a way to cool faster than Newton's law indicates
> is possible with external cooling, and that is to cool internally.

Of course, this is without a doubt the case.

>         The internal cooling concept could even be extended below 
> freezing by "perfusing" with cold gaseous helium as was suggested
> by Darwin, Leaf (et al?) a few years ago.

I'm also far from certain that gas perfusion would function. The
equipment to do it has never really been built, and the difficulties
involved are vast. I have pretty strong suspicions (but I must admit,
no more than suspicions) that attempts to do this will result in
mechanical failure of large portions the circulatory system sufficient
to prevent perfusion long before the bulk of the body actually gets
cold enough to be interesting.

>         How could we flash freeze an intact brain?  Mr. Coetzee's 
> reference to the Peltier effect is ridiculous, as Perry Metzger has 
> explained.  The only way I can think of (other than installing a 
> nanotech Peltier cooler in every cell ;) ) is to perfuse the brain 
> with a non-toxic mixture of some *enormously* endothermic (heat
> absorbing) reactants.
[...]
>         I doubt that any simple, known endothermic reaction has
> a delta H large enough to do this job.[...]

Indeed, I have strong suspicions that the "rules of the game" prohibit
such a reaction from proceeding at a wide enough range of temperatures
to keep it interesting. The reactants could, of course, be changed
through time, but again, I don't think that could be done with
anything like the speed needed for flash freezing.

In any case, both Brian and I agree in principle that Mr. Coetzee's
odd comments on peltier effect based flash freezing has no resemblance
to a well founded engineering proposal.

Perry

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=3600