No substitute shall hereafter be employed in any Department; and the
head of any Department in which substitutes are now employed may appoint
any of such substitutes to take the place of his principal, or to any
place of lower grade: _Provided_, That no substitute shall be
appointed as herein authorized until he shall have passed an appropriate
examination by the Civil Service Commission and his eligibility shall
have been certified by said Commission to the head of the Department in
which he is employed.
Approved, August 3, 1888.