Why Did So Many Soldiers Die?

Loss of life in the Civil War nearly equaled all loss of life in all wars up to the Vietnam War.  Most would think the primary cause of death for soldiers in the Civil War would have been death by the enemy, but in reality it was death by medicine.

There is no denying the carnage of the Civil War.  Armies had up to 200,000 or more soldiers on the field.  The sheer quantity of soldiers on the field could turn rivers red with blood.  Battle strategy was antiquated, not having changed since Napoleonic times.  Soldiers would advance in rows, shoulder to shoulder, head on with the enemy, with little or no cover to protect them.  Weapons technology had advanced from muskets to rifles.  Rifles shot further, had greater accuracy, and more deadly ammunition. 

The violence of the Civil War was brutal, but the violence of medicine was worse.  Limited by the lack of medical professionals, ambulances, and hospitals and complicated by the size of the armies, wounded soldiers would sometimes lie on the battlefield for days without water or aid. Neither side was prepared for the massive casualties of the war. Even worse was the lack of medical knowledge.  Germ theory had not yet been discovered, so surgeons didn’t wash in between patients and when they did wash it was often in dirty water.  Disease was rampant in the army camps, and treatment for disease was primitive. Prisoners of war suffered the most from disease.  In the end, disease killed almost double the soldiers of the Civil War combat itself.

Which was responsible for more death, combat or medicine?  Why?

How could such great loss of life been prevented in the Civil War?