An unusual opportunity was afforded during the late war to the medical profession of this country to obtain definite information from the reports of the examinations of the selective service men in regard to the physical condition of the young men of this country between the ages of 21 and 30 years.
During the World War, more than 4,000,000 men were enrolled in the military service in the Army, and slightly more than 600,000 in the Navy and Marine Corps. Of the number in the Army, approximately 2,700,000, or more than 70 per cent., came in in accordance with the provisions of the Selective Service Act. Never before in the history of this country had such a large number of men been examined physically for the military service, for whom accurate records of the examinations were preserved. Prior to this time the largest army assembled in the United States was