This relationship can, perhaps, be usefully illustrated by reference to the possession, and the right to possession, of land which is held by a trustee subject to a private trust. As a legal owner, and subject to any disposition of the right, such as would occur upon the granting of a lease, the trustee has at law the right to possession of the land and, unless somebody else is in possession, under him or adversely to him, he also has the legal possession of the land. He may maintain trespass against anyone who infringes that possession, and ejectment against any person who, without his consent, takes possession. At law a cestui que trust has no right to possession. He cannot sue the trustee at common law in ejectment .... . If the trustee holds as a bare trustee for a beneficiary absolutely entitled, that beneficiary is, in equity, entitled to put into possession if he so wishes, but he cannot sue the trustee in ejectment. His right can be enforced only by an order made in the exercise of the equitable jurisdiction of the court. If necessary, the court will, upon an appropriate indemnity being given, compel the trustee to allow the beneficiary to use his name to bring ejectment. When placed in possession by the trustee, at law the beneficiary is merely tenant at will of the trustee, the tenancy being determinable at law at any time on demand of possession by the trustee ... . As a corollary, the trustee might at law determine the beneficiary's tenancy and recover the land from him in an action for ejectment, and the beneficiary would have no legal defence. He would, of course, have an equitable defence which he has long been able, by statute, to plead in the action at law.'