It shall be lawful for an executor, administrator or trustee to delegate by deed to a trustee company either alone or jointly with any other corporation or person, as his or her attorney, all such trusts and powers as may by law be delegated, and all acts done by the trustee company within the scope of such delegation shall, in favour of any persons dealing with the trustee company without notice of the death of, or revocation of authority by, such executor, administrator or trustee, be valid and effectual notwithstanding such death or revocation.