A. authorized B. to collect certain rents, and directed him to apply them, (1) to the payment of certain demands due to third. persons, and then to the payment of a mortgage held by B. B. collected the rents, which did not amount to enough to pay the preferred demands, and appropriated them all to his own claim. In an action by A. for the money, Held, that B. could not set off his own demand. Tagg v. Bowman, 108 Pa. St. 273. See references under Sec. 307.