Explanation:

 Explanation IV states that any matter which might and ought to have been made ground of defence or attack in such former suit shall be deemed to have been a matter directly and substantially in issue in such suit. It thus lay down the principle of ,constructive resjudicata. When any matter which might and ought to have been made a ground of defence or attack in a former proceeding but was not so made, then such a matter in Me eye of law, to avoid multivllcity,of litigation and bring about finality in it. is deemed to have been constructively in issue and therefore is taken as decided. (Workmen v. Board of Trustees, Cochin Port Trus).