twelve o'clock
He pressed the bell . `` Marston , '' he said to the man who presently came , `` you must be very tired , but Dr. Cairn will be here within an hour . Tell him that I have gone to Sir Michael Ferrara 's . '' `` But it 's after twelve o'clock , sir ! '' `` I know it is ; nevertheless I am going . '' `` Very good , sir . You will wait there for the Doctor ? ''