The casualty numbers for the Civil War are difficult to fully grasp. From a national population of a little over 31,000,000, at least 625,000 men died. Recent calculations estimate the number of Civil War deaths to be closer to 750,000.
A comparison that may illustrate the horror of this reality is that in World War II, a population more than four times larger had 291,500 deaths.
Union soldiers killed in action were 67,088 while 43,012 died of their wounds for a total of 110,100 killed in battle. However, 224,580 died of disease. Others died of random accidents or as prisoners of war.
Confederate casualties, from a smaller population, follow a similar pattern. Killed and mortally wounded were 94,000 while 164,000 died of disease.
Why did so many of the wounded die? And why were the deaths from disease around twice as great as deaths from battle? A clear reason: medical ignorance.
Many soldiers died from minor wounds that became infected. Civil War doctors paid no attention to clean hands and sterilizing scalpels was not considered. After a battle, the surgeon moved from one patient to another, wiping his hands or scalpel on whatever was handy. The medical understanding of the time was that infections came from poisons in the air. When it was available, medical staff sprayed chemicals such as bromine in the hospital ward and they poured iodine, bromine and carbolic acid over body waste and pus from wounds. Not to kill bacteria—which they didn’t know about—but to purify the air.
Epidemics of measles, smallpox and erysipelas raged through crowded army camps while commanders worried that a harmful mist might be rising from a nearby river.
Doctors noticed that erysipelas and hospital gangrene spread from patient to patient which they believed was because the poisonous odor from the diseased person contaminated the air. We now know that both are caused by bacteria which was carried from one soldier to another by the doctor himself. As they gained experience, some doctors concluded that a patient with gangrene should be put in a separate tent so the miasma rising from his wounds would not endanger others. A wise move, although the logic behind it was mistaken.