"THE GREAT IRONY is that in the beginning, the gut was all there was. "We're basically a highly evolved earthworm surrounding the intestinal tract," Khoruts commented as we drove away from his clinic the last day I was there. Eventually, the food processor had to have a brain attached to help it look for food, and limbs to reach that food. That increased its size, so it needed a circulatory system to distribute the fuel that powered the limbs."