ONE

      One Man’s Trash

      On November 19, 1849, a male rhino tripped and fell at the London Zoo. He hit the ground hard and cracked a rib, which stabbed one of his lungs. The next day, the zookeeper saw him try to vomit. Blood and mucus shot out of his nose and mouth. A week later, the rhino died.

      How would you get rid of a dead two-ton rhino? The zookeeper got rid of him the same way we’d get rid of an old couch or fridge. He offered the rhino for free. “You haul him, he’s yours,” the zookeeper said.

      You know that saying, “One man’s trash is another man’s treasure”? In this case, one man’s dead rhino was another man’s … I’m tempted to say rhinestone. But this was true treasure to the right man, a free two-ton diamond. That man was the scientist and professor Richard Owen, head of the Hunterian Museum in London.

      Richard Owen had urged the London Zoo to buy the rhino ten years earlier, even though rhinos don’t come cheap, so he was sad that the animal died at a younger age than expected. But he jumped at the chance to dissect any dead animal. He would measure all the organs. He’d study how the pieces of the animal fit together, as if it were a puzzle. Then he’d write a scientific paper on what he’d learned.

      If you’ve ever dissected a worm, you know it can be hard to find their tiny body parts, like the brain. Imagine Richard Owen dissecting the rhino. Organs that get lost in a worm are huge in a two-ton animal. He even found a gland that no one had ever noticed before—not in any animal, not in any human. The gland was the size of a plump green pea. I saw this gland at the Hunterian Museum in London, preserved in a jar.

      Where My Story Begins

      My road to the rhino gland started at a free health fair. At 6:30 one Saturday morning, I left home without eating only to stand in a long, long line. Who were all those people, awake and dressed at that hour? I inched to the front of the line. There, a young man in a crisp white coat tried to take my blood. Not until his third sharp jab into my arm did his syringe fill with a deep red.

      A month later the results of the blood test came in the mail. I tore into the envelope as if it held a report card that would reveal my bright future or punish me for my past. How did my body do this year? Numbers that were too big or too small were lined up on the far right. Some I don’t worry about. I’m not going to stop eating butter and ice cream just because a number is high. But I saw something new on that list: high calcium. That’s good, right? I eat yogurt every day and swallow calcium pills because calcium builds bones. Didn’t seem like a bad thing to have high calcium.

      “Don’t worry. It’s not cancer,” my doctor said when I showed him the results of the test. Of course not, I thought. It’s just calcium. How little I knew. He pulled a book off a shelf and opened it to a line drawing of the inside of a neck. Then he pointed to a small oval shape filled in with the color red. And, for the first time, I heard the name of the gland that Richard Owen found in his rhino: parathyroid.

      A bad name, if there ever was one. The Greek word para means beside or near. So parathyroid means near the thyroid. True, these glands are near the thyroid. But this is like naming your son for the boy next door, calling him Para-Bob or Para-Sam. The name made sense to someone. Maybe because blood vessels connect the thyroid and parathyroid, like water and sewer pipes that serve both your house and the one next door. Still, every other organ in the body gets its own name. And never mind that a number of lofty words start with para, like paramedic. To me, para sounds like trouble. Think parasite or paranoia. See what I mean? So for now, I’ll give the parathyroid gland a nickname—the PT gland.

      Built-In Spare Parts

      Most of us have four PT glands. They’re tucked behind the thyroid, arranged in pairs on each side of the windpipe in an upper and a lower set. Often the size of a small grain of rice, they can look pear-shaped or flat like a lentil. Their color varies from a grayish white to a reddish brown. Fat can make them look yellow. In any case, their color is not the same as the thyroid’s, which makes the smooth, shiny glands easier for a surgeon to see.

      The