8 a.m. -- "Mike" and his team started rounds, bustling down the halls with the jocular efficiency that marks the beginning of the long day "on call." Mike was cocky, rested, eager to make a good impression. "You should have been here last week," he boasted. "The team was really busy."

Now the load was light: only 22 patients split between two interns, with a resident supervising. "But we could get killed tonight," he added. It was Monday, always a heavy day. He ducked in and out of rooms, listening to chests and checking each patient's lab results and treatment plan. It was 9:30 a.m. before he had seen them all.

As rounds ended, Mike was summoned to deal with the day's first crisis: a malaria patient had walked out of the hospital before finishing treatment.

10:45 a.m. -- At teaching rounds, an intern who had worked the preceding day and night presented his new patient to the teaching physician. The woman had a complicated lung problem. The other interns were quizzed on the patient's X-ray (Mike missed a large pneumonia) and the specialist embarked on a lecture. Within a few minutes, the intern responsible for the patient was fast asleep -- too exhausted from his 28 hours on duty to benefit.

1:30 p.m. -- The lunch conference over, Mike ran to the lab to check morning blood results on his current patients. The critical blood counts on the diabetic with the urine infection were missing; the technician had missed the vein, and no one had told him. Cursing, he rushed upstairs to draw the blood himself.

2:30 p.m. -- The team had four admissions, and two of the new patients were Mike's. He went to collect his medical bag from the residents' lounge and swore again: his instruments were gone. He settled down to a furious half hour of paging other interns before he found the one who had borrowed his equipment. At 3, he began the careful questioning of his first patient, a 57-year-old woman with a stroke and dangerously high blood pressure.

4 p.m. -- As Mike finished examining the stroke patient, his resident summoned him upstairs. The medical student with Mike's other admission had called about the patient, a young man with chest pain.

The patient was lying on a table, breathing fast and burning with fever.

The medical student had wondered about a collapsed lung, but Mike's resident had been more worried about a blood clot.

A lung scan showed that half of the man's right lung was neither inflating nor receiving blood. This went against a blood clot and in favor either a collapsed lung or pneumonia, so the medical student called for a repeat X-ray. A blood test showed the man's blood had become low in oxygen, and he was given a high-flow oxygen mask.

As Mike's resident hurried downstairs to check the new X-ray, Mike and the medical student drew more blood tests. The patient's blood pressure was dropping alarmingly: They ordered new intravenous solution, ran fluid into the vein full tilt, and began collecting specimens to check for infection. Downstairs, the resident called the intensive care unit. The patient's X-ray showed a pneumonia that had filled half the lung within six hours.

10 p.m. -- As the man with pneumonia was wheeled off to the intensive care unit, Mike wolfed down a roast beef sandwich. The cultures were sent, the antibiotics in the bloodstream. The intensive care intern would take over, but Mike had two new admissions yet to see, and his stroke patient's blood pressure had not yet come down. He ordered a new drug for her, then ran some blood samples down to the lab. In the cafeteria, he pocketed one of the snacks set out for the doctors on duty. He was still wide awake, the adrenaline flowing, but he had hours of paper work ahead.

1 a.m. -- Mike was fading. His third patient had had a rare disease called lupus, but it was too late at night for him to spend as much time talking to her as he would have liked. Luckily, she was only in for a biopsy -- the write-up would be short. He dropped into a chair to read the chart of what he hoped would be his last admission -- a man who needed rehabilitation following surgery for a brain tumor. It was a depressing case: the man now had speech difficulties. But he would require little medical care, and Mike might get an hour or two of sleep tonight.

6 a.m. -- Mike stumbled into the on-call room and collapsed into bed. His three charts had taken almost four hours to complete. The stroke patient had been difficult: sorting out her medicines, reconstructing her symptoms from his sketchy, 12-hour-old notes, trying to remember which cerebral artery supplies the cortex that moves the leg and which cranial nerves come off the brain stem. He had meant to schedule a scan of her head for the morning. Now it would have to wait.

6:15 a.m. -- His beeper jolted him awake. He dialed the nurses' station and was told that a patient with alcoholic liver disease had developed a fever.

Three minutes later, the beeper went off again. Another patient was having chest pain and trouble breathing -- the nurse said it had been going on "for a couple of hours."

Mike said he would be down "in a little while." He rolled over and, in spite of himself, dropped back to sleep. The beeper squawked again. His stroke patient was vomiting.

He dragged himself out of bed and, bleary-eyed went to see the stroke patient. A reaction to her medicine, he told himself. It was almost 7 a.m. when he got to the man with chest pain, and he spent 45 minutes examining him and studying his chart before he decided the pain was probably not a heart attack. He ached all over. It was 7:45 a.m. -- time for a quick shower, rounds, and another 10 hours of work ahead before he could go home.