These are "fiduciary duties" - the highest duties imposed by law.

Yet such cases are also explicable upon the ground that a person i-rho promises to perform, or performs, a duty imposed by law provides no consideration.

While there is no general duty imposed by law upon employees to cooperate with their employer, they must not betray their employer's trust, for instance by giving away trade secrets.

Manslaughter by omission occurs where the accused in breach of a duty imposed by law fails to carry out an undertaking, whether contractual or otherwise, and the victim dies as a result.

Marriage is a civil institution, originating in a civil contract whereby a man and a woman mutually agree to become husband and wife and to discharge toward each other the duties imposed by law.

When one turns to consider cases where a pre-existing duty imposed by law is alleged to be valid consideration for a promise, one finds cases in which public policy has been held to invalidate the consideration.

If it be a duty imposed by law upon a party regularly subpoenaed to attend from time to time to give his evidence then a promise to give him any remuneration for loss of time incurred in such attendance is a promise without consideration.

The appointment and removal of conservators, and of the guardians of minors, mentally incompetent persons and spendthrifts, and in relation to the duties imposed by law on such conservators and guardians, and the management and disposition of the estates of their wards.

In cases where the discharge of a duty imposed by law has been treated as valid consideration, the courts have usually (but not invariably) found an act over and above, but consistent with, the duty imposed by law: see Williams v. Williams,(above, p. 218).