Every trust company which at the time this act takes effect lawfully possesses and exercises the power, for hire, to examine titles to real estate, to procure and furnish information in relation thereto, and to guarantee or insure the title to real estate to persons interested, in such real estate or in mortgages thereon, against loss, by reason of defective title or other encumbrances of or upon, such real estate, shall continue to possess such power, but no other trust company shall hereafter have or exercise such power.