To take examples from the legislation of our own time, the Act passed in 1845, for punishing the malicious destruction of works of art with whipping, was most properly made prospective only.

Whatever indignation the authors of that Act might feel against the ruffian who had broken the Barberini Vase, they knew that they could not, without the most serious detriment to the commonwealth, pass a law for scourging him.

On the other hand the Act which allowed the affirmation of a Quaker to be received in criminal cases allowed, and most justly and reasonably, such affirmation to be received in the case of a past as well as of a future misdemeanour or felony.

If we try the Act which attainted Fenwick by these rules we shall find that almost all the numerous writers who have condemned it have condemned it on wrong grounds.

It made no retrospective change in the substantive law.