172.650.  Certificates to remain unconvertible — partial liquidation, when. — 1.  All of the state certificates of indebtedness issued to, and part of, the seminary fund, whether original certificates or renewals thereof, are hereby confirmed as sacred obligations of the state to said fund, and they shall be and remain nonnegotiable, unconvertible and untransferable from the purposes of their issue, and they shall remain so much of the permanent seminary fund as is represented by their amounts, respectively, until they shall be liquidated by the general assembly by appropriation and payment of the face amounts thereof to the seminary fund.

  2.  The general assembly may provide for the partial liquidation of any and all of said certificates by appropriation and payment to the seminary fund of a portion or portions of the face amounts thereof and, in any such event, a new certificate of indebtedness shall issue for the balance of the face amount of such partially liquidated certificate which remains unpaid after such partial liquidation.