Lucid Intervals

In medical jurisprudence. Periods in which a lunatic is so far free from his disease that the ordinary legal consequences of insanity do not apply to acts done therein. LUCRATIVA CAUSA (Lat.) In Roman law. A consideration which is voluntary; that is to say, a gratuitous gift, or such like. It was opposed to onerosa causa, which denoted a valuable consideration. It was a principle of the Roman law that two lucrative causes could not concur in the same person as regarded the same thing; that is to say, that, when the same thing was bequeathed to a person by two different testators, he could not have the thing (or its value) twice over. Brown. LUCRATIVA USUCAPIO (Lat.) This species of usucapio was permitted in Roman law only in the case of persons taking possession of property upon a decease of its late owner, and in exclusion or deforcement of the heir, whence it was called "usucapio pro haerede." The adjective "lucrativa" denoted that property was acquired by this usucapio without any consideration or payment for it by way of purchase; and, as the possessor who so acquired the property was a mala fide possessor, his acquisition, or usucapio, was called also "improba," i. e., dishonest; but this dishonesty was tolerated (until abolished by Hadrian) as an incentive to force the haeres to take possession, in order that the debts might be paid and the sacrifices performed; and, as a further incentive to the haeres, this usucapio was complete in one year.

Brown.