At any regularly called general or special meeting of the shareholders a written vote received by mail from any absent shareholder, and signed by him, may be read in such meeting, and shall be equivalent to a vote of such of the shareholders so signing: Provided, he has been previously notified in writing of the exact motion or resolution upon which such vote is taken, and a copy of same is forwarded with and attached to the vote so mailed by him. In case of sickness or other unavoidable absence of a member, he shall be allowed to vote by proxy in writing; but no member shall vote more than one such proxy. (1915, c. 144, s. 12; C.S., s. 5253.)