Yes, some historians have pointed out this caused a persistent undercount of fatalities in battles of the era. The number of wounded who subsequently died of their injuries was actually quite high, so most battles of the day killed more people than our historically-accepted counts appear to indicate.
This is much less a problem today – even in WWII, the vast majority of people considered “wounded” were eventually saved. This was due mostly to the development of antibiotics and the dedication of more resources to evacuating and treating the wounded. Nowadays they can save you from most things that haven’t outright killed you, and the loss of wounded who reach hospitals behind the line is something less than half a percent.
As per the OP, historian John Keegan compared the aftermath of the Battle of Waterloo to a natural disaster.
Gettysburg was a “surprise!” battle, but when it was known a battle was coming it wasn’t uncommon for both sides to go ahead and dig some graves before it started (usually given to laborers rather than soldiers). IIRC Napoleon had a unit of gravediggers. My grandfather’s job in WW1 was building coffins after an ankle injury left him unable to march.
One of the reasons that Grant was so hated in the South (the main reason of course being he was winning) was that he stopped the previous tradition of allowing southerners to collect their dead after a northern victory. Before this regardless of who won in a battle between the Army of Northern Virginia and the Army of the Potomac an unarmed detail from the other side was allowed to come and deal with its dead. I’m not sure if Grant had a strategic purpose for doing this (i.e. soldiers using it for reconaissance) or if it was just, like Sherman, a “this is war, there’s nothing chivalrous about it” thing.
One of the most famous stories about graves in the Civil War is from after the Battles of Chattanooga when Union soldiers were burying the dead and asked Maj. Gen. George Thomas (“The Rock of Chickamauga”) whether they should go through the dead to group them by state before burying. His response- which varies with the account- was to the effect of “No, mix 'em up. I’m goddamned sick and tired of hearing about state’s rights.”
The U.S. Civil War was really the dawn of modern embalming as mentioned above. (Civil War embalming picture.) Lincoln’s own body was embalmed constantly on the long trip back to Springfield and was still said to be in remarkably good shape when viewed again 40 years later.
I think the worst job would be identifying the corpses…and getting them ready to be shipped home. Where I live (New England) every old cemetary has a large number of Civil war graves…how they got those guys home is beyond me.
The undertakers must have viewed the Civil War as a business bonanza.
I think it was in Garry Will’s book Lincoln at Gettysburg, there are descriptions of the haphazard burials that occurred during and immediately after the battle. Men buried or half buried where they fell. Farmers turning up bodies in and around their fields.
In WWII burial was as described by another poster above - wherever possible. After WWII the US Graves Registration unit re-interred every US soldier they were able to locate. In Europe the families were offered the choice to bring the remains home. Despite their efforts, 30,000 US soldiers remained missing in action*. On the Russion front, the longer period of active war, the number of troops, the conditions, all led to the necessity of mass graves and marginal burial practices.
(* When I first learned that there were 30,000 missing US soldiers from WWII, it seemed unrealistic to expect (as most people seem to expect today), whether in a war or a civil disaster, that we should be able to recover remains of every one of those who died.)
This is absolutely the case. Modern weapons can completely vaporize people, and modern battle can make eyewitness accounts less available. When being bombed, troops are not only head-down, but if they’re smart, widely spaced so that a given bomb doesn’t kill too many at once. If a fuel-air explosive hits a foxhole 300 yards away while the air is full of flying metal and dirt, there may be no eyewitnesses, and the pressure and fire could completely disperse bodies. These people will probably be listed as missing.
I have always thought that the insistence on recovering every missing soldier (which as far as I know began in the Vietnam War) was wrong-headed for a particular reason: it’s my understanding that many people known to have been killed were deliberately listed as “missing” so their family could continue to receive government benefits. I could be wrong about this but I swear I’ve seen it more or less admitted. Certainly it began as an act of kindness, but it runs into a problem when people endlessly politick for missions to search for these “missing” service people whose superiors know for a fact are actually dead, but cannot admit it.
While I have no doubt that is partially true in World War 2, I would hazard a guess that the vast majority of those still listed as MIA after the war were naval and air crews, mostly involved in the Pacific. The vastness of the ocean would just make accounting for every missing aircraft or submarine to be impossible.
