In any case founded on contract, when any part of the principal or interest shall have been paid, or an acknowledgment of an existing liability, debt or claim, or any promise to pay the same shall have been made, an action may be brought in such case within the period prescribed for the same, after such payment, acknowledgment or promise; but such acknowledgment or promise must be in writing, signed by the party to be charged thereby.
R.L. 1910, § 4663.