All licenses and certificates heretofore legally issued by authority of law in this State permitting the holder thereof to practice medicine in all of its branches, or to treat human ailments without the use of drugs and operative surgery, and which are valid and in full force and effect on the taking effect of this Act, shall have the same force and effect, and be subject to the same authority of the Department to revoke or suspend them as licenses issued under this Act.
225 ILCS 60/48