Any person now holding a provisional professional, a permanent State certificate, a State normal school certificate, a State normal school diploma, a provisional college certificate, a permanent college certificate, a temporary or permanent certificate for teachers of kindergartens, drawing, vocal music, mechanical drawing, physical training, and other special branches, issued by the Superintendent of Public Instruction¹ of this Commonwealth, a special temporary certificate, a special permanent certificate, a standard temporary certificate, a standard permanent certificate, issued by the Department of Public Instruction as provided by law, shall hereafter continue to possess the same rights and privileges with respect to the practice of the art of teaching as heretofore, and may register such certificate under the provisions of this act within two years from the date of the approval of this act, subject, however, to the right of the department to suspend or revoke such registration for causes set forth in this act and subject to the right of said department to require such person to register limited certificates annually as in this act provided.