Any person acting as guardian shall have the right to demand and recover of any obligor in any bond or the maker of any other instrument in writing, payable to him as guardian, and held by him for the benefit of his ward, not only the principal sum due, with interest thereon after the rate prescribed by law; but also, when the interest on the principal sum is not paid punctually at the time stipulated in such bond or writing, to demand and recover interest upon the interest so due and unpaid.