On appeal to this Court, it was held, 1. That possession of the plaintm was sufficient to enable to maintain this action againsta mere trespasser: that the fact of ownership by a slave is not ipso facto, a feiture under the Act of 1740, P. L. 171-2; but the forfeiture under that Act, is not complete, until seizure and condemnation. 2. that the act of 1827, p. 77, which declares what shall be a lawful fence, does not authorize the killing of a horse, which breaks into a field so enclosed.