In fact, scientists say it has not yet been possible to thaw and revive to a functioning state any organ, except, some content, the small intestine in dogs. The biggest human tissues that can be frozen and returned to viability are single cells, very early multi-celled embryos, and a few selected thin tissues such as bone, corneas, cartilage and heart valves. But the cryonics movement, however far out it seems, does raise intriguing questions piquing a growing interest. About 650 people, many of them college educated and some of them in their early 30s and 40s, have already signed up with Alcor in Riverside, Calif., the American Cryonics Society in Sunnyvale, Calif., or Michigan's Cryonics Institute. Frozen heads Another 35 people or so are already in the deep freeze, and 15 Alcor members have just their heads frozen in the belief that science will be able to regenerate their bodies if it has developed the technology to thaw their heads.
Participants have little in common aside from their belief in cryonics.
Spread across the country, they come from all walks of life. Alcor reports a handful of clients in Massachusetts and about 50 from New England. That pays for freezing and upkeep in the hereafter, when the cryonically suspended are put into human-sized thermos bottles and cooled by liquid nitrogen to minus 320 degrees Fahrenheit. The process of cryonic preservation begins immediately after death is pronounced. At the mortician's, blood is drained and an organ- preservation fluid is put in.