The regimental ambulance corps consisted of two litter bearers from each company. Two junior officers from the line companies supervised the unit at the brigade level. The assistant surgeon from each regiment followed closely behind the main body of troops in the attack. Regulations prohibited the doctors from directing their exclusive attention to any single wounded man. Other rules explicitly forbid them from leaving the field to escort any of the wounded to the rear. The soldiers in the line of battle also had strict orders against helping their injured comrades while the fighting was underway. Any man who dropped out of formation to care for one of his friends without permission was subject to severe punishment. By the time of Gettysburg, the standard allocation was reduced to only two ambulances for each regiment. A single team of two horses or mules pulled those small wagons.