“ Mr. Justice HARLAN, upon consideration of the confession of error filed here by the respondent and in light of the record, would vacate the judgment of the Court of Appeals of the State of Georgia and remand the case for further appropriate proceedings. ”

“ We hold that a tender back is also not requisite when it is pleaded that the carrier and the employee entered into the release from mutual mistake as to the nature and extent of the employee's injuries. We have held that an express agreement of an injured employee who obtained funds from a carrier to help defray living expenses first to return the sum paid as a prerequisite to the filing and maintenance of an action under the FELA was void under § 5 of the Act. ”