Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That each and every free able-bodied white male citizen of the respective states, resident therein, who is or shall be of the age of eighteen years, and under the age of forty-five years (except as is herein after excepted) shall severally and respectively be enrolled in the militia by the captain or commanding officer of the company, within whose bounds such citizen shall reside, and that within twelve months after the passing of this act.