“Well, I’ll tell you one thing,” he said, looking down at his feet. “They ain’t worth much.”

Fifteen minutes later we were on Constitution, passing the Department of the Interior while the Washington Monument watched over the Mall, where tents had been set up to celebrate African American art, and vendors sold Eastern Shore crabs and T-shirts from the backs of small trucks. The grass between kiosks was depressingly layered with yesterday’s trash, and every other minute another ambulance screamed past. We had driven in circles several times, the Smithsonian coiled in the distance like a dark red dragon. There was not a parking place to be found and, typically, streets were one way or abruptly stopped in the middle of a block, while others were barricaded, and harried commuters did not yield even if it meant your running into the back of a parked bus.

“I tell you what I think we should do,” I said, turning on Virginia Avenue. “We’ll valet park at the Watergate and take a cab.”

“Who the hell would want to live in a city like this?” Marino griped.

“Unfortunately, a lot of people.”

“Talk about a place that’s screwed up,” he went on. “Welcome to America.”

The uniformed valet at the Watergate was very gracious and did not seem to think it odd when I gave him my car and asked him to hail a cab. My precious cargo was in the backseat, packed in a sturdy cardboard box filled with Styrofoam peanuts. Marino and I were let out at Twelfth and Constitution at not quite noon, and climbed the crowded steps of the National Museum of Natural History. Security had been intensified since the Oklahoma bombing, and the guard let us know that Dr. Vessey would have to come down and escort us upstairs.

While we waited, we perused an exhibit called Jewels of the Sea, browsing Atlantic thorny oysters and Pacific lions’ paws while the skull of a duckbill dinosaur watched us from a wall. There were eels and fish and crabs in jars, and tree snails and a mosasaur marine lizard found in a Kansas chalk bed. Marino was beginning to get bored when the bright brass elevator doors opened and Dr. Alex Vessey stepped out. He had changed little since I had seen him last, still slight of build, with white hair and prepossessed eyes that, like those of so many geniuses, were perpetually focused somewhere else. His face was tan and perhaps more lined, and he still wore the same thick black-framed glasses.

“You’re looking robust,” I said to him as we shook hands.

“I just got back from vacation. Charleston. I trust you’ve been there?” he said as the three of us boarded the elevator.

“Yes,” I replied. “I know the chief there very well. You remember Captain Marino?”

“Of course.”