The life of a Civil War regimental band member wasn't all treble clefs and drum sticks. During combat, they were pressed into service as field medics and ambulance drivers, running onto contested battlefields and dragging the wounded off for medical treatment.
The bands were generally raised just before the units they would serve. Some were contracted by state legislatures and others by officers in units they had begun enlisting.
The initial purpose of the band was to help get attention of potential enlistees as a sort of marketing campaign.
When the units began training and later deploying, the bands would help keep morale up and sometimes assist with music for drills.
But when the units took to the field, there were generally few uses for a full brass band in the middle of combat. Some were ordered to play music in the middle of the fray, like when a Confederate band played during the Battle of Gettysburg and men on both sides heard the music.
Some musicians became runners, carrying messages as the bullets flew. But most were sent to remove the wounded.
Massachusetts musician John D. Whitcomb later said:
I put some considerable value on the service of the band in the several affairs the regiment was engaged in as an Ambulance Corps. . . . The mere fact of one member of the band being twice required to cross the line of fire of both forces, undoubtedly saved the lives of several members of our own regiment from the fire of one of our own batteries, several members of our own regiment having already been killed by the unfortunately located battery. . . . The bandsmen had been well taught by the surgeon how to give first aid to the wounded, and how to use stretchers, bandages and tourniquets. We were to go with the regiment into battle, rescue the wounded, if possible, and carry them to the field hospital. We were liable to be sent as messengers on dangerous errands.
In 1862, Congress passed a bill to muster out nearly all regimental bands, leaving some at the corps and brigade levels as well as drummers, buglers, and fifers in the companies.
Unsurprisingly since many of the men had worked in battles like Whitcomb's, they were happy to take their last paychecks and leave.
Later the same year, Maj. Jonathan Letterman created the Ambulance Corps out of specially trained soldiers, along with the medics, nurses, and surgeons who had existed since the Revolutionary War.
The Ambulance Corps proved itself at the Battle of Antietam when they successfully recovered all the wounded in 24 hours. (The musicians sometimes took over a week to do the same after some battles.)