DEC. 8 AT THE ARMY'S 21ST Combat Support Hospital was tree-lighting day. But it didn't end on a festive note.

Doctors, medics, and other personnel were having a relatively light day with no incoming wounded. "We never use the Q word around here"-meaning quiet-said Col. Carol McNeill. "Then it's sure to change."

During the lull the hospital chaplain, Capt. Dallas Walker, gathered the medical team to light the Christmas tree. Men and women, doctors, nurses, medics, and administrators clumped into the intersecting tent between the trauma tent and operating rooms to sing "White Christmas" and "Jingle Bells."

Hospital commander Col. Douglas Liening stepped up to turn on the lights-a ceremony timed to coincide with the Christmas tree lighting at Fort Hood, Texas, the unit's home base. Chaplain Walker ended with prayer: "Father, we do thank You for this life that You've given each one of us. Now continue to protect us and watch out for us. And be with our dear loved ones back home."

Then it was back to work. At 6 p.m. the radio crackled to life: "Medevac, medevac, medevac." That was the first alert that wounded soldiers would be arriving soon.

This hospital is the Army's largest medical facility in Iraq outside a field hospital in Baghdad. Located near the town of Balad, halfway between hot zones at Tikrit in the north and Fallujah in the south, the 21st CSH-known in Army lingo as "the cash"-absorbs much of the war's trauma.

Medical staff here have seen more than 14,000 patients since the hospital opened at the end of April. Those include victims of combat, accidents, and general medical cases ranging from asthma attacks and hives to pneumonia and heart attacks. The 84-bed facility is a revolving door: Patients are treated quickly and returned to duty; or, in trauma cases, stabilized so they can be transported to the Army's full-fledged medical center at Landstuhl, Germany.

The hospital takes up one quadrant of Camp Anaconda, at 15 square miles the largest U.S. base in Iraq. The hospital runs on 300 active-duty personnel. They work 8- or 12-hour shifts but in reality are on call 24 hours a day.

Lt. Col. Kimberly Kesling is currently the only orthopedic surgeon on staff-and seven out of every 10 surgical procedures are orthopedic. Physicians frequently show up in off-duty shorts and T-shirt to don surgical gloves and go to work. Inside the windowless maze of tents, it's hard to know whether it's day or night. And, anyway, the lights are always on.

Why would physician specialists choose Army life? "I know this is where God wants me," said Col. Russ Martin, a general surgeon. "Pay for Army doctors is not the same as private physicians, but it is very good, very comfortable."

Col. Martin, director of resident training at the Fort Hood hospital, volunteered to deploy for Operation Iraqi Freedom because he knew there was a shortage of field physicians. "I don't see a lot of friends out there [in private practice] happy, and I am very happy with what I am doing."

At 7 p.m. more details trickle in. A Stryker, the Army's newest fighting vehicle, has rolled into a canal. Three urgent-care gurneys are prepared in the EMT (or trauma unit). Medics peel off sweaters, laugh, and sing instructions to keep tension at bay. "It's about to get hot in here," said one.

A nurse arrives with, "Who, what, when, and where?" She rubs sleepy eyes and departs after sizing up the staff level and concluding she won't be needed.

Then the final radio call: one minute out, but only one patient, in stable condition. There's no time to wonder about the changing numbers or the delay in arrival. The chopper has touched down and the ambulance flashes its headlights into the gravel path by the EMT door. An officer rolls out its back doors ahead of the litter. "Stryker vehicle rolled over into a ditch of water. It's on its head right now," he says.

The victim is conscious and moving. Once on the table, medics and nurses crowd in, slice open his pants and shirt, and go to work. His temperature is good and in a matter of minutes he is upright, wretching.

But the news coming through the ward isn't good. Two soldiers in the Stryker remained trapped under water too long. They were dead on arrival. A third was given CPR for 40 minutes before he also died. After the survivor is stabilized and X-rayed, one of the attending physicians will head outside to pronounce the fatalities.

The EMT ward clears slowly but the mood changes instantly. The medical team is sober and curt. "It is very, very hard when we lose three guys," explains nurse Capt. Shirley Daniels. "No one takes it well. We've been doing it for nine months. And it's getting old."

Central Command said attacks on coalition forces across Iraq averaged 50 a day at the height of bombings in November-the worst casualty month yet for U.S. forces in Iraq. Last week they said attacks had fallen to about 20 a day.

The slowed tempo is welcome news here. But it doesn't change the toll for the military's caregivers. The camp itself comes under attack too. Overnight, two artillery rounds are unloaded against suspected insurgents.

"It's hot and cold. You can have 28 attacks and only four wounded. Or one attack with 28 casualties," said Maj. Douglas Boyer, an internal-medicine physician.

Most here are seeing combat duty for the first time. And most will be around well into next year. March is the earliest anyone currently on duty is likely to go home. "There is a lot of trauma here. A lot of trauma," said Col. Carol McNeill, deputy commander for nursing and a 23-year Army active-duty officer. "We see multiple amputations, eye injuries, bellies opened up-the kind of things that stay with you."

The bombing of UN headquarters in Baghdad sent 24 trauma victims to the 21st, including a man with a 5-foot metal window-frame rod protruding through his skull. Technicians had to saw the rod in order to carry him through the trauma unit doors. He survived, but lost an eye.

Trauma victims instantly marshal these hospital workers, but the seriously wounded rarely make headlines. During the first week of December, arriving combat casualties averaged about three a day. A soldier came in with the lower part of his face blown off. His vehicle hit an improvised explosive device, or IED, just outside the camp. When the convoy slowed after the explosion, an attacker shot him in the face.

A severely wounded soldier was driven up to the gate in a Bradley after he was hit by an armor-piercing artillery round. Medics worked to revive him, but he died in the trauma unit.

In another recent case, about 60 hospital personnel volunteered their own blood for a severely wounded soldier after failing to stop near-fatal bleeding. He needed 21 units of whole blood before surgeons located and fixed a contracted vessel from a leg amputation.

The hospital has two recovery units set aside for Iraqi prisoners of war.

"Sometimes they will bring in an American soldier, and right behind him the insurgent who shot him," said Col. McNeill. No one anticipated the hospital would take on prisoner patients, but they have to be completely healed, according to Col. McNeill, before they can be moved to a detention facility. "We treat the patient, regardless of nationality," said Maj. Boyer. But the prisoners have a separate ward guarded by military police.

Defense officials are continuing the embed policy for journalists (which put a BBC camera crew and WORLD in the trauma unit on Dec. 8), but medical personnel here are frustrated by the way news media are covering casualties. Capt. Troy Smith, a respiratory therapist, says reports should not distinguish between "war" casualties before the official end of hostilities and current casualties.

Those reports may exact political damage on President Bush for declaring an end to hostilities last May, but to the staff here, the slant makes it look like the military isn't up to the present threats. "This never was a major conflict; it was a guerrilla war from the outset and it still is. They are trying to maim our soldiers, and that's our whole focus out here," he said.

Dec. 8 may be the only reprieve combat hospital workers have for awhile. The following day the radio was crackling early with reports of bombings at both ends of the sector: A car bomber had driven up to a checkpoint in Mosul and detonated himself among U.S. troops, and soon after there was another explosion in Baquba. None of the wounded showed up at the 21st until sometime after lunch, when one of the Mosul injuries just suddenly appeared at the tarmac. He had already been operated on at a smaller hospital in Mosul, then flown here.

One of the medics who flew with him produced a baseball-sized piece of shrapnel covered in blood. He had saved the chunk, which had wedged itself into the soldier's face. Gauze draped the young man's lower face, but bleeding from his facial wounds continued and some of his vitals were wavering. Scanning his paperwork, one of the nurses noted that yesterday was his 18th birthday. Doctors readied him for X-rays and more surgery, before he would be sent up to Germany.