The next time you go to the doctor, check out the plaques on the wall. One of them, usually the biggest, will be decorated with an intriguing symbol: two snakes climbing up a winged staff.
Ask your doctor what this symbol means, and you'll probably get this line: The staff is called the caduceus. It's the sign of Hermes, god of alchemists, and the symbol of the American Medical Association.
But that is only half the truth.
Meet the guinea worm. It hangs around in ponds, too small to see with the naked eye. If you drink guinea-worm-infected water, one of these beasties may find its way into your stomach. From there, it will make its way to one of your legs, working chemical magic to hide from your immune system. It will grow much bigger, as long as two feet.
And it will have babies.
Adult guinea worms may be invisible to your immune system, but their kids have a different strategy - they set off every alarm they can.
Why? Well, overexcited immune defenses are tricky, painful, dangerous things. With all those baby guinea worms raising a ruckus, your infected leg becomes inflamed. Huge blisters appear, which makes you run screaming to the nearest pond to cool them down.
Very clever. The young guinea worms smell the water and pop out of the blisters. Then they settle down to begin their wait for the next unwary drinker of pond water.
Ew, yuck, repeat.
Guinea worms have been pulling this trick for a long time. In fact, it was thousands of years ago that ancient healers found out how to cure them. The procedure is simple, in theory. Just pull the adult worms out of the victim's leg. But there's a trick: If you pull too quickly, the worm breaks in half, and the part left inside rots away, causing a terrible infection. The patient usually dies.
Here's how the doctors of the ancient world did it:
Carefully draw one end of the worm out, and wrap it around a stick. Then, over the next seven days or so, wind the guinea worm outward, like reeling in a fish in very slow motion. That's right: It takes seven days. Don't rush! It won't be the most enjoyable week you ever spent, but at the end you'll have your body back in good working order. And you'll also have a stick with a wormy thing wrapped around it.
And this icky leftover will become the symbol of medicine.
Ew.
But maybe it's not such a weird symbol. Historians figure that guinea-worm removal was the first-ever form of surgery. Back then, it was probably a pretty amazing feat, pulling a snake out of a human body. Maybe the doctors hung the snake-wrapped stick on their walls afterward, just to show that they could get the job done.
So the next time you're at the doctor's office, be on the lookout for this heartwarming symbol of the ancient healing arts. (And don't believe all that crap about the great god Hermes; it's all about the guinea worms. )