Lady Audley's Secret, Mary Elizabeth Braddon

Mad-houses are large and only too numerous; yet surely it is strange they are not larger, when we think of how many helpless wretches must beat their brains against this hopeless persistency of the orderly outward world, as compared with the storm and the tempest, the riot and confusion within: -- when we remember how many minds must tremble upon the narrow boundary between reason and unreason, mad to-day and sane to-morrow, mad yesterday and sane to-day.