Voluntarily took command of troops and attacked and defeated hostile Indians he met on the way. Surg. Irwin volunteered to go to the rescue of 2d Lt. George N. Bascom, 7th Infantry, who with 60 men was trapped by Chiricahua Apaches under Cochise. Irwin and 14 men, not having horses, began the 100-mile march riding mules. After fighting and capturing Indians, recovering stolen horses and cattle, he reached Bascom’s column and helped break his siege.