Doctors at University Teaching Hospital do their best to improvise, as Desai once did, to make sick people well again, even if it is with an off-the-shelf power tool. And there have been some significant material improvements at the hospital since Desai left. Makasa took me to the intensive-care unit, where a doctor from Uzbekistan was supervising the installation of monitors, ventilators and electrically operated beds that any modern hospital would be happy to own, all donated by the Japanese government. Much of the equipment in the operating theaters was new, and the theaters themselves were being renovated. The hospital had a new M.R.I. machine, a new CT scanner and new dialysis machines. What it does not have — what can’t be donated — is enough doctors.

I stopped by the neonatal-intensive-care unit, which many years earlier drove Kunj Desai to tears. Desai stayed up all night manually pumping air into a baby’s lungs, because there was no available ventilator. The next night, he returned to find that the baby had disappeared from the ward. He did not ask about the boy’s fate, but surmised that the doctor who followed him on duty had not been able to continue ventilating the boy by hand. I looked around at the dozens of babies in the unit. There were three new ventilators, also donated by the Japanese, but none were plugged in; the staff had not yet been trained to use them. I asked Jackie Banda, the doctor in charge of the unit that day, how long the unit had been without ventilators. “We’ve had none for the last two to three years,” she said.

Kasonka, the managing director of the hospital, said that he didn’t blame Desai for leaving to pursue his surgical education. As we spoke in his office, I told him that Desai wanted to become a laparoscopic surgeon. At that, Kasonka sat forward in his chair with interest. Zambia, he said, had no surgeons performing this less-invasive surgery, though the Netherlands had recently donated a laparoscope.

“If I have to say something to Dr. Desai, it is: ‘Hey, Dr. Desai, I know you have now acquired extra skills in surgery including laparoscopy,’ ” Kasonka said. “I have got a state-of-the-art laparoscope — please come back and practice.’ You see, he will pack up his bags and come back.”

When I returned from Lusaka last May, I went to visit Desai at his home in Jersey City. Desai’s wife, Bhavana, a pharmacist who also is Zambian of Indian descent, and their 17-month-old daughter, Kaiya, greeted me at the door of the town house they rent in a gated community that sits on Newark Bay, across from the airport. Some relatives were visiting from England, and we discussed the trying times of Liverpool, the soccer team Desai supports. Desai turned up a few minutes later, in scrubs, after a 14-hour shift.

Like Ofori-Amanfo, Desai feels a strong need to help his country. “It is still my homeland,” he told me when we first met. “It is still where I plan to die. I have spots picked out where I plan to retire.” In the course of our conversations, I noticed an unmistakable look of anger pass over Desai’s face sometimes, and I suspected his anger was directed in several directions at once: at the failings of his own country, at the inequities of the globalized economy, at himself. We in the West create the demand for his talents and are the beneficiaries. The first doctor to look after my son was a Nigerian pediatrician, whose country suffers from a chronic shortage of doctors and who could, presumably, help many more children in more dire need there.

In our conversations and e-mail, Desai seemed to be exploring a way to go home. He’s an only child who worries about abandoning his parents in their last years, and he wants Kaiya to grow up as a Zambian, not as an American. But he despairs of the public health system in Zambia and can’t stomach the idea of catering to the wealthy in the private sector. He talked of returning to open up his own private clinic, which would serve everyone, not just the wealthy. Or perhaps he could work for a foreign aid agency there, he said.