OLD AGE. This needs no definition. Sometimes old age is the cause of loss of memory and of the powers of the mind, when the party may be found non compos mentis. See Aged witness; Senility.

OLD NATURA BREVIUM. The title of an old English book, (usually cited Vet. N. B.) so called to distinguish it from the F. N. B. It contains the writs most in use in the reign of Edward III, together with a short comment on the application and properties of each of them,

OLD TENURES. The title of a small tract, which, as its title denotes, contains an account of the various tenures by which land was holden in the reign of Edward III. This tract was published in 1719, with notes and additions, with the eleventh edition of the First Institutes, and reprinted in 8vo. in 1764, by Serjeant Hawkins, in a Selection of Coke's Law Tracts.

OLERON LAWS. The name of a maritime code. Vide Laws of Oleron.

OLIGARCHY. This name is given to designate the power which a few citizens of a state have usurped, which ought by the constitution to reside in the people. Among the Romans the government degenerated several times into an oligarchy; for example, under the decemvirs, when they became the only magistrates in the commonwealth.

OLOGRAPH. When applied to wills or testaments, this term signifies that they are wholly written by the testator himself. Vide Civil, Code of Louisiana, art. 1581: Code Civil, 970; 6 Toull. n. 357; 1 Stuart's (L. C.) R. 327; 2 Bouv. Inst. n. 2139; and see Testament, Olographic; Will, Olographic.

OMISSION. An omission is the neglect to perform what the law requires.

2. When a public law enjoins on certain officers duties to be performed by them for the public, and they omit to perform them, they may be indicted: for example, supervisors of the highways are required to repair the public roads; the neglect to do so will render them liable to be indicted.

3. When a nuisance arises in consequence of an omission, it cannot be abated if it be a private nuisance without giving notice, when such notice can be given. Vide Branches; Commission; Nuisance; Trees.

OMNIA PERFORMAVIT. A good plea in bar, where all the covenants are in the affirmative. 1 Greenl. R. 189.