23In absence of express condition, no casualties in feus created after commencement of Act. Increase or reduction of feu-duty or periodical additional payment may be stipulated
In feus granted after the commencement of this Act, the annual feu-duty shall be of fixed amount or quantity, and no casualties or duties shall by law, irrespective of express condition or covenant, be payable to the granter of the feu, or his successors in the superiority, and it shall not be lawful to condition or stipulate for any casualty to be paid on the succession of an heir or the acquisition of a singular successor, or in any way except at fixed intervals; but it shall be lawful to condition or stipulate for a permanent increase or reduction of the feu-duty, or for payment of a casualty in the form of a periodical fixed sum or quantity, provided that the amount of such increase or reduction, or of such periodical additional sum or quantity, shall be certain, and that the time or times at which such additional sum or quantity shall be exigible, or from and after which such increase or reduction is to have effect, shall also be certain and not dependent upon any event or occurrence except the occurrence or recurrence of the time or times at which under the terms of such condition or stipulation the periodical additional sum or quantity is made exigible, or the increase or reduction of feu-duty is to have effect.