midnight
Then , dreading sleep more than ever , she took up her `` sentry-go '' on the landing , glancing in at the sick-room at every turn in her walk . The hours dragged wearily on . Tresler gave no further sign . It was after midnight , and the girl 's eyes refused to keep open any longer ; added to which she frequently stumbled as she paced to and fro . In desperation she fetched the lamp from the sick-room and passed into her own , and bathed her face in cold water . Then she busied herself with tidying the place up . Anything to keep herself awake .