How have the courts interpreted the terms of a trust agreement where a life-tenant was ordered to repay his trust fund to his executors?

All of the parties dealt with the fund knowing it to be the subject of a trust, and incapable of alienation, and that its trust character followed it into the hands of any person receiving it with the knowledge of the facts. The executors had authority, upon receiving satisfactory security for its return, to deliver possession of the money to the life-tenant for the duration of his life, and so far the contract was valid; but this was the extent of their power over it, and this plainly appears from the face of the contract. The condition inserted, that the money was not to be repaid in the event of the life-tenant leaving issue him surviving, was clearly illegal, and in law impossible of performance, and could not be set up as a defense against an action by the executors to recover possession of the trust fund. Wetmore v. Porter, supra. The complaint sets out, and the proof establishes, all of the circumstances attending the loan of money; and it is clear, upon the whole case, that the plaintiffs were entitled to recover. No question arises over a misjoinder of actions, or as to the mode of trial, for the record discloses no objection upon these subjects.