All deeds, mortgages, or other instruments in writing, relating to or affecting any real estate situated in this State, wherein a corporation was the grantor, mortgagor, grantee or mortgagee, which have been acknowledged or proven prior to the effective date of Section 14 1/2 of “An Act to provide for the appointment, qualification and duties of notaries public and certifying their official acts and to provide for fines and penalties for the violation thereof,” approved April 5, 1872, as amended, before any notary public, justice of the peace or other officer authorized by the laws of this State to take acknowledgments of such instruments in writing, when so acknowledged or proven in conformity with the laws of this State, shall be adjudged and treated by all courts of this State as legally executed and acknowledged or proven, notwithstanding such acknowledgments or proof of the execution thereof were taken before a notary public, justice of the peace or such other officer who was, at the time of such acknowledgment, a stockholder or officer of such corporation; and all such acknowledgments or proofs of such deeds, mortgages, or other instruments in writing, heretofore taken before any such notaries public or other officers are hereby legalized.