When a soldier was shot in Renaissance Europe, a barber was frequently on hand to pouring scalding oil of elder over the wound. But when Ambroise Pare ran out during a French military campaign in 1530, he improvised by applying a cold salve of egg yolk, oil of rose and turpentine.
To his surprise, the soldiers healed faster and suffered less -- and the old treatment faded into history.
During amputations, Pare also found a safe way to stop soldiers from bleeding to death. Rather than searing the vessels with hot irons, a technique that was as likely to injure as heal, he pinched them with clamps and tied them off with sutures.
Though nobody would sanely argue that war is needed to push medicine ahead, some of the medical advances we take for granted were made by people coping with the pressures -- and horrors -- of war.
"Every time there's been a major war, there has been a major leap in learning," said Air Force Col. Joseph Palma, a professor at the Uniformed Services University of the Health Sciences in Bethesda.
Battlefields, with their large concentration of the sick, injured and dying, provide a unique opportunity to observe what works and what doesn't. "An army at war is a gigantic clinical trial," said Dr. Robert Joy, a retired professor of medical history at the Uniformed Services school.
Facing possible slaughter, armies have sought novel treatments so they could return soldiers to battle. Though healers didn't understand the disease process until the 19th century, practitioners since ancient times learned remedies through trial and error.
Roman physicians, realizing that their gods couldn't cure everything, bandaged wounds to stop bleeding, amputated limbs to prevent gangrene, offered opium to ease suffering and invented tools to extract arrows. Some of their know-how was borrowed from Greek doctors captured as slaves.
One of medicine's first controlled trials occurred during a conflict in 1747, when Dr. James Lind of the British Royal Navy tried different treatments on 12 sailors who were sick with scurvy. Those who received two lemons and an orange each day recovered, while others given traditional remedies such as vinegar and sea water got worse.
It would be another 40 years before the Navy heeded the lesson and distributed citrus to its sailors, who came to be known as "limeys," and longer still before scientists learned the key ingredient was vitamin C.
Weather tests an army as cruelly as bullets and bombs. As Napoleon's army marched into Russia in 1812, Czar Alexander I declared, "We will leave it to our climate, our winter to conduct the war against him." He was nearly right.
Starvation and Cossacks helped drive the Grande Armee into retreat, but the bitter winter slowed the army with frostbite. Along the way, the emperor's chief medical officer noticed that soldiers who warmed their limbs by the fire were sure to develop gangrene and required amputation.
Baron Dominique-Jean Larrey, who made a practice of not walking too close to the campfires, realized that frostbitten men should be transported to the rear where they could be rapidly -- and fully -- thawed. To accomplish this, Larrey devised one of the first medical rescue vehicles, a horse-drawn wagon that served as a prototype for the first ambulance.
Though scientists didn't understand until the 1870s that germs caused diseases from anthrax to dysentery, basic ideas of sanitation were being applied to military camps. In the Civil War, for instance, doctors knew that keeping tents and dirt latrines separate was not simply a matter of aesthetics but of health, said Joy.
Still, camps were strewn with trash and infested with flies, fleas and mosquitoes. Doctors performed surgery in blood-soaked gowns, and merely rinsed instruments between uses. Two soldiers died of disease for every one from injuries.
Despite the conditions, surgeons developed better techniques of tying off bleeding arteries and extracting bullet fragments, said Dr. Alfred Jay Bollet of Yale University, who has written extensively on Civil War medicine. Dentists devised facial splints for fractures caused by gunshots to the jaw. And for the first time, doctors kept detailed patient records of injuries and treatment.
Women serving on the battlefields of America and Russia provided first aid and comfort and organized field hospitals. Florence Nightingale's care of the wounded in the Crimean War of the 1850s led to professionalization of nursing. Clara Barton, who aided Union troops in the Civil War, later founded the American Red Cross to provide relief for victims of war and disaster.
Wartime discoveries sometimes required human guinea pigs. In the Spanish-American War, where troops were more likely to succumb to yellow fever than bullets, Maj. Walter Reed deliberately exposed volunteers, including himself, to mosquitoes -- proving that the bugs carried the disease. A campaign to destroy breeding grounds in Cuba soon wiped out the disease there, and the success was repeated a few years later during the digging of the Panama Canal.
The idea of banking blood grew out of World War I. Before the war, transfusions were performed by hooking donors directly to recipients, but this proved useless at the front.
The problem spurred Dr. Oswald H. Robertson, an American physician serving on the Western Front, to find a way to store blood for faster delivery to the wounded. The key was adding anti-clotting compounds, and keeping the bottled solution on ice.
Though penicillin, the first antibiotic, was developed in the 1930s, the U.S. government pushed it into wide-scale production during World War II while military doctors worked out the proper dosing. The mortality rate among soldiers with bone infections dropped from nearly 100 percent to about 25 percent, Joy said.
Other advances included the use of DDT to fight typhus, a deadly infection spread by fleas. The insecticide stemmed epidemics among dockworkers in Alexandria, Egypt, and the citizenry in Naples, Italy, and threatened Allied troops, said Joy..
In Korea and Vietnam, the United States employed helicopters to get injured troops to medical care within the crucial "Golden Hour," after which the odds of survival fall steeply. The term is widely credited to Dr. R Adams Cowley, a World War II doctor who in the early 1960s founded the University of Maryland's Shock Trauma Center, where patients are ferried by helicopter.
Korea also gave birth to MASH units, portable tent hospitals that moved with the ever-changing field of battle. The units have been widely employed by groups aiding civilian refugees around the world.
Today, medics in the Persian Gulf carry new technologies to stanch life-threatening blood loss. A powder called QuikClot works by sucking water out of blood, promoting clotting at wound sites.
They're also trying out new gauze bandages that can stop bleeds in two minutes thanks to a natural clotting factor sprayed over the synthetic mesh.
Dr. Thomas Scalea, chief physician of Shock Trauma, said he can imagine civilian paramedics and surgeons using the bandages to save people with injuries to the liver, pelvis and neck -- areas of profuse bleeding against which traditional gauze is often useless.
"We've been hearing about it for years," said Scalea, adding that he is anxious to try the bandages at Shock Trauma. "Everybody knows we should be using it."