To the unschooled eye, a healthy human liver is neither
particularly ugly nor appealing. Brownish-red inside the body,
it pales to a pinkish-purple once a surgeon cuts off the blood
flow and removes it. You might mistake the liver for a lady's
evening bag if it didn't glisten like something from the
butcher's case. No other organ is so taken for granted. Small
children understand that the heart goes thump, that the brain
adds two plus two, that the lungs capture each breath, that
other organs process food. The liver, meanwhile, cleanses the
blood of poisons, makes protein and bile and does scores of
other tasks, not all of which scientists fully understand. Human
genius has created kidney dialysis machines and artificial
hearts, but it has yet to mimic the life-force character of the
only internal organ that can regenerate. "The liver is an
amazing organ," says one specialist. "I don't want to comment on
other organs, but the heart"--a dismissive shrug, a sly
grin--"the heart is a piece of muscle. It is a pie