Francis Ackerman, a volunteer from New York, gleaned fresh clothes from the fields at the Third Battle of Winchester, in September 1864. His account of finding a riderless horse mingles the grotesque tragedy of battle with the dry humor so characteristic of War memoirs. “I discovered a horse with one of his legs shot off, on his back a good outfit,” he wrote. “Feeling rather lively from life inside my clothes,” he “concluded to examine the wounded horse, and was rewarded by finding a clean full suit of underwear. I stripped on the battle field, and with thankful heart put it on, the first change I had in six weeks.” More fastidious men changed into clean underwear faithfully — once a week.
The New York Times’ Disunion Blog on Civil War Underpants

Francis Ackerman, a volunteer from New York, gleaned fresh clothes from the fields at the Third Battle of Winchester, in September 1864. His account of finding a riderless horse mingles the grotesque tragedy of battle with the dry humor so characteristic of War memoirs. “I discovered a horse with one of his legs shot off, on his back a good outfit,” he wrote. “Feeling rather lively from life inside my clothes,” he “concluded to examine the wounded horse, and was rewarded by finding a clean full suit of underwear. I stripped on the battle field, and with thankful heart put it on, the first change I had in six weeks.” More fastidious men changed into clean underwear faithfully — once a week.

The New York Times’ Disunion Blog on Civil War Underpants