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 I will also say that I haven't been following such research for years and my own information may be quite out of date.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 Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=1479