1908 – Congress passed legislation that created the Medical Reserve Corps, the Army’s first federal reserve force. From this pool of trained medical professionals, the secretary of War was able to order Reserve officers to active duty during time of emergency. In June 1908, the first 160 Reserve medical officers received their commissions. This number grew to about 360 by 1909, to 1,900 by 1916, and to 9,223 by 1917. The concept of bringing civilian professionals into the Army in a disciplined and quickly-accessible manner soon expanded beyond the medical profession and beyond officers, becoming the modern US Army Reserve.