Section 31
SEC. 31. No person shall be excused from testifying or from producing any book, document, or paper in any investigation or inquiry by or upon the hearing before the Commission, when ordered so to do by said Commission, except when the testimony or evidence required of him may tend to incriminate him. Without the consent of the interested party, no member or employee of the Commission shall be compelled or permitted to give testimony in any civil suit to which the Commission is not a party, with regard to secrets obtained by him in the discharge of his official duty.