From Blackstone’s Commentaries, Volume I pp. 89-90.
‘Where the common law and a statute differ, the common law gives place to the statute; and an old statute gives place to a new one.
And this upon a general principle of universal law, that “leges posteriores priores contrarias abrogant:” consonant to which it was laid down by a law of the twelve tables at Rome, that “quod populus postremum jussit, id jus ratum esto.” But this is to be understood only when the letter statute is couched in negative terms, or where its matter is so clearly repugnant that it necessarily implies a negative.
As if a former act says, that a juror upon such a trial shall have twenty pounds a year; and a new statute afterwards enacts, that he shall have twenty marks: here the latter statute, though it does not express, yet necessarily implies a negative, and virtually repeals the former. For if twenty marks be made qualification sufficient, the former statute which requires twenty pounds is at an end.
But if both acts be merely affirmative, and the substance such that both may stand together, here the latter does not repeal the former, but they shall both have a concurrent efficacy. If by a former law an offence be indictable at the quarter-sessions, and a latter law makes the same offence indictable at the assizes, here the jurisdiction of the sessions is not taken away, but both have a concurrent jurisdiction, and the offender may be prosecuted at either: unless the new statute subjoins express negative words, as, that the offence shall be indictable at the assizes, and not elsewhere.’