My Lords, we contend strongly that all the positive rules and injunctions of the law, though they are merely positive, and do not contain anything but mere matters of regulation, shall be strictly observed. The reason is this, and a serious reason it is: official tyranny and oppression, corruption, peculation, and bribery are crimes so secret in their nature that we can hardly ever get to the proof of them without the assistance of rules, orders, and regulations of a positive nature, intended to prevent the perpetration of these crimes, and to detect the offender in case the crimes should be actually perpetrated. You ought, therefore, to presume, that, whenever such rules or laws are broken, these crimes are intended to be committed; for you have no means of security against the commission of secret crimes but by enforcing positive laws, the breach of which must be always plain, open, and direct. Such, for instance, is the spirit of the laws, that, although you cannot directly prove bribery or smuggling in a hundred cases where they have been committed, you can prove whether the proper documents, proper cockets, proper entries in regular offices have been observed and performed, or not. By these means you lock the door against bribery, you lock the door against corruption, against smuggling and contraband trade. But how? By falling upon and attacking the offence? No, by falling upon and attacking the breach of the regulation. You prove that the man broke the regulation, and, as he could have no other motive or interest in breaking it, you presume that he broke it fraudulently, and you punish the man not for the crime the regulation was meant to prevent, but you punish him for the breach of the regulation itself.
Next to the breach of these positive instructions, your Lordships will attend to the consequent concealment and mystery by which it was accompanied. All government must, to preserve its authority, be sincere in its declarations and authentic in its acts. Whenever in any matter of policy there is a mystery, you must presume a fraud; whenever in any matter of money there is concealment, you must presume misconduct: you must therefore affix your punishment to the breach of the rule; otherwise the conviction of public delinquents would be unattainable.