Section 155. Discharge and cancellation of mortgages by the state

The
  treasurer's receipt, countersigned by  the  comptroller,  setting  forth
  that  the  whole  sum secured by the mortgage held by the state has been
  paid, shall be a sufficient discharge of the mortgage, and  the  officer
  in whose office such mortgage is recorded shall record such receipt as a
  satisfaction  of  the  mortgage and satisfy the mortgage of record. When
  any part or subdivision of any lot mortgaged to or  purchased  from  the
  state,  for  which  a  separate  account  has  been opened, is paid, the
  comptroller shall execute a discharge of such part or  subdivision  from
  such mortgage.
    If  a  map  and  survey of the whole lot is filed with the comptroller
  showing particularly a part or subdivision for which no separate account
  has been opened, and the owner thereof pays into the treasury  its  full
  proportion  of  principal and interest unpaid, and satisfactory proof is
  furnished the comptroller that the residue  of  the  lot  is  sufficient
  security  for  the sum remaining unpaid, he may execute a like discharge
  of such part or subdivision.
    The comptroller may cancel and discharge any mortgage, on satisfactory
  proof that the moneys loaned and secured  by  such  mortgage  have  been
  fully  paid to the officers authorized by law to receive the same if the
  mortgage remains uncancelled and undischarged of record.