X-Message-Number: 1479
Date: 20 Dec 92 21:56:06 EST
From: Thomas Donaldson <>
Subject: Re: cryonics: #1471 - #1474

With respect to the posting of A.Davidson:

Daedalus, as you well understand, writes his columns with the intent to
amuse. That means, among other points, that he has no reason to try to
get his facts straight. I, too, have found him very funny sometimes.

HOWEVER the first point to make about his writings on cryonics is that
his whole idea depends on a WRONG assumption. At least when freezing
kidneys, slow freezing and rapid rewarming generally works much better
than rapid freezing (regardless of the rate of warming). The same is 
apparently true of brain tissue, but (and cryonicists deplore this 
situation and have been trying hard to amend it) far less work has been
done on freezing brains than on freezing kidneys.

As to the physics of masers he proposes to use, I don't know of anyone
who has tried his suggestion. Knowing Daedalus, I'd suggest that if it
could work it would require much more finesse with equipment than we
presently have. But they DO use magnetic fields to lower temperatures
from, say, 1 degree K down to closer to absolute 0 K. If the substance
responds to magnetism then we can lower its temperature in a magnetic
field and then remove the field: the temperature goes down even more...
of course not to absolute zero. I will also say that I haven't been
following such research for years and my own information may be quite
out of date.

Finally, on the issue of memory storage, a lot has happened since his
1968-69 columns. Even though electric currents play a big role in 
brain processing, and may hold memory for less than a second, every-
thing else is chemistry of one kind or another (including the chemistry
by which a neuron grows a new synapse).          

So IF we can either lower the temperature with minimal damage, or find
ways to repair damage after/during the warming process, virtually all
memories should remain intact. This problem may turn out to be easy
or very hard, depending on lots of conditions, among which is what we
finally work out is/are the processes by which our memory forms in
our brain and is retained there --- questions on which there is intensive
research and a good prospect of a solution in the NEAR future.
				Best and long life,
					Thomas Donaldson

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