law: 37. Evidence before the Controller.-
  Subject to any rules made under section 44, in any proceeding under this Act before the Controller, the evidence shall be given by affidavit in the absence of directions by the Controller to the contrary; but in any case in which the Controller thinks it right so to do he may take evidence viva voce in lieu of or in addition to evidence by affidavit or may allow any party to be cross-examined on the contents of his affidavit.