All undistributed interest, standing to the credit of any patients' or inmates' fund in any State institution of this Commonwealth, and which cannot be properly apportioned among the persons having an interest in such fund, or who have heretofore had an interest in such fund, shall, on or before the thirty-first day of May, one thousand nine hundred and twenty-nine, be paid by the board of trustees, officer of such institution, or person in charge of said fund, into the General Fund of the State Treasury.
72 P.S. § 3605