The effects of relentless (often religious-based) warfare in 16th-first half of 17th centuries brought horrifying new ways to suffer and die. Due to the widespread emergence of firearms and cannons, soldiers faced gunshot wounds, burns (often caused when the equipment blew up on the combatants intending to use their weapons), and loss of limbs. Although no one yet understood how infection worked, battle medics did make enormous advancements in treating injuries.
The French surgeon Ambroise Paré (1510-1590) was particularly important, using the scientific method before it was even known as such. For the gunshot wounds, for instance, he ran an experiment that saved the lives of many. After a French campaign at the Castle of Villane in 1536, he started out treating soldiers with gunshot injuries in a traditional way, by pouring boiling oil over the wounds to cauterize them, and then stuffing the openings with all sorts of material. This caused exquisite pain and infection, but doctors had been following techniques of Ancient Roman writers (who argued that wounds should be filled) and contemporary physicians who thought gunshot would poison the blood, and could be stopped with boiling oil. Paré decided to treat half his patients with the traditional method, and half with a mixture of egg yolk, oil of roses, and turpentine. When he saw that the latter group didn’t develop fever or infection, he changed his practice.
Paré made progress treating burn wounds as well. He experimented on a young boy who had been badly burned with a mixture of salt and a paste of onions — he got these ingredients from a local woman healer and used them instead of what the local apocathery had prescribed. The result was so successful that soldiers in Russia were using the onion-and-salt mixture hundreds of years later.
Here you see two images of prosthetic legs illustrated by Paré in his _The Works of That Famous Chirurgional_ from 1634. Notice that the pair on the left were formed from wood, made for a poorer victim, while the other shows a limb made out of iron, which only the wealthy could afford.
Sources: _The Four Horsemen of the Apocalypse _ by Andrew Cunningham and Ole Peter Grell, Cambridge UP, 2000, Pp 125-129