What is here meant by abuse of trust, is the exercise of a power usurped over strangers, under favour of the powers properly belonging to the trust. The distinction between what is here meant by breach of trust and what is here meant by abuse of trust, is not very steadily observed in common speech: and in regard to public trusts, it will even in many cases be imperceptible. The two offences are, however, in themselves perfectly distinct: since the persons, by whom the prejudice is suffered, are in many cases altogether different. It may be observed, perhaps, that with regard to abuse of trust, there is but one species here mentioned; viz. that which corresponds to positive breach of trust: none being mentioned as corresponding to negative breach of trust. The reason of this distinction will presently appear. In favour of the parties, for whose benefit the trust was created, the trustee is bound to act, and therefore merely by his doing nothing they may receive a prejudice: but in favour of other persons at large he is not bound to act: and therefore it is only from some positive act on his part that any prejudice can ensue to them.

IPML Chapter 16 Section 2 Part 5