Section 152. Conditions of sale

At  a  sale under such foreclosure the
  comptroller shall require the purchaser to pay, at the time of the sale,
  the costs and expenses thereof, and at least one-fourth of the amount so
  unpaid; and for securing the remainder of the moneys due the  state,  on
  the  execution  of a deed or of the affidavits of sale to the purchaser,
  he may accept from the purchaser a bond and mortgage to the state on the
  premises sold, payable in six  equal  annual  instalments,  with  annual
  interest at six per centum. If the mortgaged premises sell for a greater
  sum  than  the  amount so unpaid and the costs and expenses of the sale,
  the comptroller shall also require the purchaser at the time of the sale
  to  make  payment  of  such  surplus.  The  expense  incurred   by   the
  attorney-general  in any action or proceeding for the foreclosure of any
  such mortgage, shall be paid to him out of the treasury.