Death, according to Dr Herbert Mentius, proprietor of a medical research institute "is not natural at all. It's really an avoidable mistake." Mentius is a character in The Methuselah Enzyme (1970), one of a score of novels by Fred Mustard Stewart (9/17/32-2/7/07) who, dead at 75, did not avail himself of the DNA modifications plausibly set out in that brisk shocker.