Castro sat in a small cramped office at the medical school of the Federal University of Rio, hunched over a laptop computer, studying real-time meteorological data displayed on the screen. He paid scant attention to the temperature and barometric-pressure readings from various stations around Rio, focusing instead on wind direction and speed.
The doctor jotted notes on a chart. Then he reviewed those notes before coming up with a hypothesis. Now he just had to conduct an experiment to see if his hypothesis was right.
Pensive, the doctor exited his browser and shut his computer down. He put the laptop in a knapsack and then picked up a mason’s leather and canvas bag from the floor beneath his desk.
Outside, it was a mild, midwinter day in Rio, temperatures in the low seventies and an ocean breeze that was northeasterly, coming down off the equator. As Dr. Castro walked, he wondered whether the breeze would stay prevailing and steady with a building warm trend or change out of the south, as the latest forecasts indicated.
“Dr. Castro? Professor?”
The doctor had hoped to get off campus quickly, but he turned. A smiling young man ran up, trying to catch his breath.
“I’m sorry, Professor,” he said. “But I have a question from last week’s lecture on retrovirus reverse transcription.”
Castro had important things to attend to, but he was devoted to his students, especially this one: Ricardo Fauvea. Ricardo reminded Castro of his younger self. Like the doctor, Ricardo had grown up desperately poor in one of Rio’s favelas and had defied the odds. Despite a public-school education, he had scored well enough on an entrance exam to earn a spot in one of Brazil’s excellent tuition-free universities. He’d done it again getting into the medical school, just as Castro had.
“Walk with me,” the doctor said.
“What’s in the bag?” Ricardo asked.
Dr. Castro flushed, slightly embarrassed. “A new hobby.”
Ricardo looked at him quizzically. “What sort of hobby?”
“Come along, I’ll show you,” he said, and hailed a taxi. “How are you anyway?”
Castro’s young protégé recounted the latest events in his life on the short cab ride to the village of Urca, on the bay in the shadow of Sugarloaf Mountain. They got out of the cab and walked the rocky shoreline to a secluded, crescent-shaped beach.
“So that’s me up to date,” Ricardo said. “How about you, Doctor?”
“I’m fine,” Castro said, walking out onto the sand and happy to see the little beach was empty. “What did you want to know about reverse transcription?”
“Right,” Ricardo said. “I wanted to know why RT doesn’t produce exact copies of viruses all the time.”
“Because retroviruses are unpredictable. I suppose that’s why I enjoy my new hobby so much.”
The doctor opened the mason’s bag, revealing the components of an Estes model rocket. “This toy is ingenious and predictable. I know for certain that if I put everything together correctly, it will fly spectacularly.”
Castro loaded the nine-inch rocket with an engine and attached it to a starter and battery. “Now, some viruses are like this toy: stable, predictable. Those kinds of viruses reproduce predictably.”
Setting the rocket on its launchpad, he said, “But retroviruses are notoriously unstable and mutate constantly. Those unpredictable ones are the ones you have to fear, because by the time you’ve figured out a cure, the one you’re trying to kill has already mutated into something else.”
Ricardo nodded his understanding, but not convincingly. “Give me an example?”
Castro thought of his private lab work but said, “The virus that causes the common cold. It’s constantly changing. That’s why so many have tried and failed to cure it. Ready?” He held out the ignition key and switch. “You do the honors.”
Ricardo smiled, took the device, said, “It’s not dangerous?”
“No,” the doctor said. “Just fun.”
His student twisted the key and flipped the switch. An intense flame shot out the bottom of the little rocket. It gathered thrust, soared into the sky, and blew a white contrail for five, maybe six hundred feet before a parachute popped open and the rocket dangled there, floating on the sea breeze.
Still northeast, Dr. Castro thought, and then he noticed the parachute stutter and float on a slightly different tangent as it fell slowly into the harbor and then sank.
“You lost it,” Ricardo said.
“Still fun,” Castro said, grinning. “You didn’t like that?”
“No, I did,” his student said. “I liked it taking off the best.”
“I kind of like the whole experience,” Castro said, laughing. “I honestly do.”
“Why, do you think?”
“I don’t know,” the doctor said. “I read about these when I was a boy, but of course we could never afford such luxuries. I suppose the rockets make me feel like the kid I was never allowed to be.”
Chapter 22