Both in the sense of obeying the law, and conforming to its general rules and policy, and also in applying to equitable estates and interests the rules by which at common law legal estates and interests of a similar kind are governed.
14. Agentes et consentientes pari poenâ plectentur. Acting and consenting parties are liable to the same punishment.
A person aiding and abetting the actual commission of a crime, either at the scene of its commission or elsewhere, is equally liable with the perpetrator, the former being a principal in the second degree, and the latter in the first degree. If A., with intent to murder, inflicts on B. an injury dangerous to life, aided and abetted by C., who is aware of the intent, they are both equally guilty and punishable.
* 15. Alienatio rei praefertur juri accrescendi. The law favours alienation rather than accumulation.
This maxim has always been the policy of our law, even from the time when the right of subinfeudation was first recognised. The statutes of De Donis, 13 Edw. I. c. 1 and Quia emptores, 18 Edw. I. c. 1, are examples in proof of this doctrine. Also the rules against perpetuities, which forbid any executory interests to take effect later than a life or lives in being or twenty-one years afterwards, allowance being made for gestation where the same actually exists.
16. Allegans contraria non est audiendus. One who contradicts himself is not to be heard.
A rule of evidence relative to the credibility of a witness. Cross-examination is frequently used to this end.
17. Allegans suam turpitudinem non est audiendus. A person boasting of his own wrong-doing is not to be heard.
When a person does an act which may be rightfully performed, he cannot say that such act was intentionally done wrongly. See In re Hallett, Knatchbull v. Hallett, 13 Ch. Div. 696, where an obiter dictum found in the judgment of the Court is as follows: “When we come to apply that principle” (i.e., the one given above) “to the case of a trustee who has blended trust moneys with his own, it seems perfectly plain that he cannot be heard to say that he took away the trust money, when he had a right to take away his own money.”
* 18. Ambiguitas contra stipulatorem est. An ambiguity is taken against the party using it.