Joel Weinstock was flying somewhere over New York or Pennsylvania when he got his crazy idea. He had been studying intestinal parasites. That day he began reading about Crohn's Disease. Why, he wondered, did people who had intestinal worms not have Crohn's and people who had Crohn's never have intestinal parasites? Could it be that worms prevented Crohn's? Naw. Impossible.

But he couldn't get the idea out of his head. In the 1940s half of American children had worms. In 1980 there were something like 10 times more people with Crohn's than in 1940. This is a pretty strong correlation. Weinstock decided to see what happened when he gave whip worm eggs to people with inflammatory intestinal disease.

In March of 1999 29 well-informed and consenting patients were given Gatorade laced with whipworm eggs. And by week 24 of the study all but one of the patients were doing better and 22 of the remaining 25 (some, understandably, dropped out of the study) were in remission. These were patients with serious and untreatable Crohn's. And having worms made them healthier.

Deborah Wade had an exceedingly bad case of Crohn's disease. She read about Weinstock's experiment and in 2007 she decided she wanted to try the worm treatment. So she found someone (a non-MD in an unlicensed Mexican clinic) who would give her a drink of worms. "The endeavor felt more like adopting a pet than modern medicine - a long, translucent, sucker-mouthed companion animal."

Deborah Wade is not cured, but she is better. And so are other people with autoimmune diseases who have been treated with worms. Why would "rewilding" your body, as the author calls it, keep autoimmunie disease under control? How does it work? They aren't really sure but it has something to do with cells produced by chronic worm infestation that help to tamp down the excessive reactions of Lupus and asthma and Crohn's.

This is just one of the dozens of puzzling and sometimes alarming stories Rob Dunn tells in his amusing book about The Predators, Parasites, and Partners That Shape Who We Are Today. The author offers some convincing explanations for how cows domesticated humans, how lice and fleas made us naked, and the exceedingly useful role of our appendix.

Most of us who are primarily readers of fiction, ex-English majors, literature junkies, are distressingly ignorant about science. This makes reading popular science written by people like Dunn and Natalie Angier so entertaining. So much is going on out there in the world of botany and astronomy and ecology. Books like The Wild Life of Our Bodies begin to give us a hint of how much we are missing.

Read Rob Dunn's blog here: http://www.yourwildlife.org/