Section 63. Interrogatories shall be filed in the clerk's office, and notice of such filing, with a copy of the interrogatories, shall be sent by the party interrogating to the party interrogated, or to his attorney of record, and the party interrogated shall file answers to such interrogatories within twenty days after such notice, unless the court otherwise orders; but no party interrogated shall be obliged to answer a question or produce a document tending to criminate him or to disclose his title to any property the title whereof is not material to an issue in the proceeding in the course of which he is interrogated, nor to disclose the names of witnesses, except that the court may compel the party interrogated to disclose the names of witnesses and their addresses if justice seems to require it, upon such terms and conditions as the court deems expedient. A party shall not interrogate an adverse party more than once unless the court otherwise orders.