Section 62. Any person against whom charges are filed shall be notified of the hearing thereof, and may appear with witnesses and be heard by counsel. If such person has left the commonwealth, or cannot be found by reasonable search, notice may be dispensed with. Said boards shall have the same powers to summon witnesses to attend such hearings, and to swear them as are conferred upon city councils and other bodies by section eight of chapter two hundred and thirty-three, and said section and sections nine and ten of said chapter shall apply to witnesses summoned as aforesaid.