John D. Billings, Hardtack and Coffee: The Unwritten Story of Army Life

The hospital tents in the Army of the Potomac were heated, for the most part, by what was called, for some reason, the California Plan. This consisted of a pit, dug just outside of the hospital door, two and a half feet deep, from which a trench passed through the tent, terminating outside the other end in a chimney, built of barrels, or in such a manner as I have elsewhere described. This trench was covered throughout its entire extent with iron plates, which were issued by the quartermaster's department for that purpose. The radiation of the heat from the plates kept the tent very comfortable.

The honor of organizing the first field hospital in tents is said to belong to Dr. B. J. D. Irwin, U. S. A., of the Army of the Ohio. It occurred at the battle of Shiloh. While establishing a hospital near the camp of Prentiss' division of that army, which had been captured the day before, the abandoned tents still standing suggested themselves to him as a convenient receptacle for his wounded. He at once appropriated the camp for this purpose, and laid it out in systematic form. It was clearly shown by this and succeeding experiences during the war that the wounded treated under canvas did better and recovered more rapidly than those treated in permanent hospitals.

As fast as they could be procured, hospital tents were furnished, three to a regiment, in accordance with the provision of Army Regulations referred to. Each regiment provided its own nurses and cooks. In general hospitals one nurse was allowed to ten patients, and one cook to thirty.

The capacity of a regimental hospital tent, like a stagecoach, varied according to the demand for room. I have said they were designed to accommodate eight. An old army surgeon says, “Only six can be comfortably accommodated in one of them, three on each side.” But when the surgeons were crowded with the wounded, it was a common practice to set two long narrow boards edgewise through the centre