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When a statute or an instrument of writing undertakes to foresee and to provide for certain contingencies, and through mistake, or some other cause, a case remains to be provided for, it is said to be a casus omissus.For example, when a statute provides for the descent of intestates estates, and omits a case, the estate descends as it did before the statute, whenever that, case occurs, although it appear to be within the general scope and intent of the statute. 2 Binn. R. 279.

When there has been a casus omissus in a statute, the subject is ruled by the common law: casus omissuset oblivioni datus dispositioni juris communis relinquitur. 5 Co. 38. Vide Dig. 38, 1, 44 and 55 Id. 38, 2, 10; Code, 6, 52, 21 and 30.