X-Message-Number: 7740
Date: Sun, 23 Feb 1997 14:26:07 -0500 (EST)
Subject: rat heart temperatures

Several recent postings have said we don't know the temperature of Mrs.
Visser's rat hearts, and therefore cannot, for example, say whether anyone
else's methods could have matched her results.

This is not really correct. The successful or partly successful hearts (five
of them in all, here in Arizona) did not have temperature probes in them,
because of possible problems with the probes interfering with the process.
BUT several very similar procedures DID have probes, and they showed
temperatures in the hearts near that of liquid nitrogen. Therefore, unless
you want to contend that there was a systematic difference in treatment of
the probed hearts vs. the non-probed hearts, it seems to me virtually certain
that all her hearts did reach temperatures close to that of LN2.

All the talk about vapor shielding, putting your hand briefly in liquid
nitrogen, etc. is just blowing smoke. A tiny little rat heart in LN2, with
slight shrouding, gets VERY cold VERY fast. (We have cooling curves.) If any
critic will put his hand (a much larger object with much more thermal
capacity and much lower surface/volume ratio) into liquid nitrogen for 30
seconds, I will come and visit him in the hospital, and buy him an attachment
for his steering wheel so he can steer one-handed. 

Robert Ettinger

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