WE HAVE, it seems, a fierce attraction for spirits: auras, angels, poltergeists, disembodied souls, out-of-body experiences. Mostly, I think, we are drawn to these things because we intuit—correctly, it turns out—that there must be more to the world than meets the eye. We inherit the spirit world from a time when our ancestors huddled in dark shelters at night and let their imaginations draw up creatures more or less like ourselves although lacking corporeal substance. But why should we care about angels when the season's first blackbirds spread their redshouldered wings? Why should we seek treasures in Heaven when year after year the fiddlehead ferns unfurl their silver croziers along the brook? Why should we look for out-of-body experiences when it is our bodies that connect us through the five open windows of our senses to the sights, sounds, tastes. smells, and tactile sensations of nature? If we want more than meets the eye, we should practice on this: the invisible flame of the DNA.